Deleted vendor folder

1 files changed, 0 insertions, 2883 deletions

diff --git a/vendor/lock_api/src/rwlock.rs b/vendor/lock_api/src/rwlock.rs
deleted file mode 100644
index cf9e8aa..0000000
--- a/vendor/lock_api/src/rwlock.rs
+++ /dev/null
@@ -1,2883 +0,0 @@
-// Copyright 2016 Amanieu d'Antras
-//
-// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
-// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
-// http://opensource.org/licenses/MIT>, at your option. This file may not be
-// copied, modified, or distributed except according to those terms.
-
-use core::cell::UnsafeCell;
-use core::fmt;
-use core::marker::PhantomData;
-use core::mem;
-use core::ops::{Deref, DerefMut};
-
-#[cfg(feature = "arc_lock")]
-use alloc::sync::Arc;
-#[cfg(feature = "arc_lock")]
-use core::mem::ManuallyDrop;
-#[cfg(feature = "arc_lock")]
-use core::ptr;
-
-#[cfg(feature = "owning_ref")]
-use owning_ref::StableAddress;
-
-#[cfg(feature = "serde")]
-use serde::{Deserialize, Deserializer, Serialize, Serializer};
-
-/// Basic operations for a reader-writer lock.
-///
-/// Types implementing this trait can be used by `RwLock` to form a safe and
-/// fully-functioning `RwLock` type.
-///
-/// # Safety
-///
-/// Implementations of this trait must ensure that the `RwLock` is actually
-/// exclusive: an exclusive lock can't be acquired while an exclusive or shared
-/// lock exists, and a shared lock can't be acquire while an exclusive lock
-/// exists.
-pub unsafe trait RawRwLock {
-    /// Initial value for an unlocked `RwLock`.
-    // A “non-constant” const item is a legacy way to supply an initialized value to downstream
-    // static items. Can hopefully be replaced with `const fn new() -> Self` at some point.
-    #[allow(clippy::declare_interior_mutable_const)]
-    const INIT: Self;
-
-    /// Marker type which determines whether a lock guard should be `Send`. Use
-    /// one of the `GuardSend` or `GuardNoSend` helper types here.
-    type GuardMarker;
-
-    /// Acquires a shared lock, blocking the current thread until it is able to do so.
-    fn lock_shared(&self);
-
-    /// Attempts to acquire a shared lock without blocking.
-    fn try_lock_shared(&self) -> bool;
-
-    /// Releases a shared lock.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if a shared lock is held in the current context.
-    unsafe fn unlock_shared(&self);
-
-    /// Acquires an exclusive lock, blocking the current thread until it is able to do so.
-    fn lock_exclusive(&self);
-
-    /// Attempts to acquire an exclusive lock without blocking.
-    fn try_lock_exclusive(&self) -> bool;
-
-    /// Releases an exclusive lock.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an exclusive lock is held in the current context.
-    unsafe fn unlock_exclusive(&self);
-
-    /// Checks if this `RwLock` is currently locked in any way.
-    #[inline]
-    fn is_locked(&self) -> bool {
-        let acquired_lock = self.try_lock_exclusive();
-        if acquired_lock {
-            // Safety: A lock was successfully acquired above.
-            unsafe {
-                self.unlock_exclusive();
-            }
-        }
-        !acquired_lock
-    }
-
-    /// Check if this `RwLock` is currently exclusively locked.
-    fn is_locked_exclusive(&self) -> bool {
-        let acquired_lock = self.try_lock_shared();
-        if acquired_lock {
-            // Safety: A shared lock was successfully acquired above.
-            unsafe {
-                self.unlock_shared();
-            }
-        }
-        !acquired_lock
-    }
-}
-
-/// Additional methods for RwLocks which support fair unlocking.
-///
-/// Fair unlocking means that a lock is handed directly over to the next waiting
-/// thread if there is one, without giving other threads the opportunity to
-/// "steal" the lock in the meantime. This is typically slower than unfair
-/// unlocking, but may be necessary in certain circumstances.
-pub unsafe trait RawRwLockFair: RawRwLock {
-    /// Releases a shared lock using a fair unlock protocol.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if a shared lock is held in the current context.
-    unsafe fn unlock_shared_fair(&self);
-
-    /// Releases an exclusive lock using a fair unlock protocol.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an exclusive lock is held in the current context.
-    unsafe fn unlock_exclusive_fair(&self);
-
-    /// Temporarily yields a shared lock to a waiting thread if there is one.
-    ///
-    /// This method is functionally equivalent to calling `unlock_shared_fair` followed
-    /// by `lock_shared`, however it can be much more efficient in the case where there
-    /// are no waiting threads.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if a shared lock is held in the current context.
-    unsafe fn bump_shared(&self) {
-        self.unlock_shared_fair();
-        self.lock_shared();
-    }
-
-    /// Temporarily yields an exclusive lock to a waiting thread if there is one.
-    ///
-    /// This method is functionally equivalent to calling `unlock_exclusive_fair` followed
-    /// by `lock_exclusive`, however it can be much more efficient in the case where there
-    /// are no waiting threads.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an exclusive lock is held in the current context.
-    unsafe fn bump_exclusive(&self) {
-        self.unlock_exclusive_fair();
-        self.lock_exclusive();
-    }
-}
-
-/// Additional methods for RwLocks which support atomically downgrading an
-/// exclusive lock to a shared lock.
-pub unsafe trait RawRwLockDowngrade: RawRwLock {
-    /// Atomically downgrades an exclusive lock into a shared lock without
-    /// allowing any thread to take an exclusive lock in the meantime.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an exclusive lock is held in the current context.
-    unsafe fn downgrade(&self);
-}
-
-/// Additional methods for RwLocks which support locking with timeouts.
-///
-/// The `Duration` and `Instant` types are specified as associated types so that
-/// this trait is usable even in `no_std` environments.
-pub unsafe trait RawRwLockTimed: RawRwLock {
-    /// Duration type used for `try_lock_for`.
-    type Duration;
-
-    /// Instant type used for `try_lock_until`.
-    type Instant;
-
-    /// Attempts to acquire a shared lock until a timeout is reached.
-    fn try_lock_shared_for(&self, timeout: Self::Duration) -> bool;
-
-    /// Attempts to acquire a shared lock until a timeout is reached.
-    fn try_lock_shared_until(&self, timeout: Self::Instant) -> bool;
-
-    /// Attempts to acquire an exclusive lock until a timeout is reached.
-    fn try_lock_exclusive_for(&self, timeout: Self::Duration) -> bool;
-
-    /// Attempts to acquire an exclusive lock until a timeout is reached.
-    fn try_lock_exclusive_until(&self, timeout: Self::Instant) -> bool;
-}
-
-/// Additional methods for RwLocks which support recursive read locks.
-///
-/// These are guaranteed to succeed without blocking if
-/// another read lock is held at the time of the call. This allows a thread
-/// to recursively lock a `RwLock`. However using this method can cause
-/// writers to starve since readers no longer block if a writer is waiting
-/// for the lock.
-pub unsafe trait RawRwLockRecursive: RawRwLock {
-    /// Acquires a shared lock without deadlocking in case of a recursive lock.
-    fn lock_shared_recursive(&self);
-
-    /// Attempts to acquire a shared lock without deadlocking in case of a recursive lock.
-    fn try_lock_shared_recursive(&self) -> bool;
-}
-
-/// Additional methods for RwLocks which support recursive read locks and timeouts.
-pub unsafe trait RawRwLockRecursiveTimed: RawRwLockRecursive + RawRwLockTimed {
-    /// Attempts to acquire a shared lock until a timeout is reached, without
-    /// deadlocking in case of a recursive lock.
-    fn try_lock_shared_recursive_for(&self, timeout: Self::Duration) -> bool;
-
-    /// Attempts to acquire a shared lock until a timeout is reached, without
-    /// deadlocking in case of a recursive lock.
-    fn try_lock_shared_recursive_until(&self, timeout: Self::Instant) -> bool;
-}
-
-/// Additional methods for RwLocks which support atomically upgrading a shared
-/// lock to an exclusive lock.
-///
-/// This requires acquiring a special "upgradable read lock" instead of a
-/// normal shared lock. There may only be one upgradable lock at any time,
-/// otherwise deadlocks could occur when upgrading.
-pub unsafe trait RawRwLockUpgrade: RawRwLock {
-    /// Acquires an upgradable lock, blocking the current thread until it is able to do so.
-    fn lock_upgradable(&self);
-
-    /// Attempts to acquire an upgradable lock without blocking.
-    fn try_lock_upgradable(&self) -> bool;
-
-    /// Releases an upgradable lock.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an upgradable lock is held in the current context.
-    unsafe fn unlock_upgradable(&self);
-
-    /// Upgrades an upgradable lock to an exclusive lock.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an upgradable lock is held in the current context.
-    unsafe fn upgrade(&self);
-
-    /// Attempts to upgrade an upgradable lock to an exclusive lock without
-    /// blocking.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an upgradable lock is held in the current context.
-    unsafe fn try_upgrade(&self) -> bool;
-}
-
-/// Additional methods for RwLocks which support upgradable locks and fair
-/// unlocking.
-pub unsafe trait RawRwLockUpgradeFair: RawRwLockUpgrade + RawRwLockFair {
-    /// Releases an upgradable lock using a fair unlock protocol.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an upgradable lock is held in the current context.
-    unsafe fn unlock_upgradable_fair(&self);
-
-    /// Temporarily yields an upgradable lock to a waiting thread if there is one.
-    ///
-    /// This method is functionally equivalent to calling `unlock_upgradable_fair` followed
-    /// by `lock_upgradable`, however it can be much more efficient in the case where there
-    /// are no waiting threads.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an upgradable lock is held in the current context.
-    unsafe fn bump_upgradable(&self) {
-        self.unlock_upgradable_fair();
-        self.lock_upgradable();
-    }
-}
-
-/// Additional methods for RwLocks which support upgradable locks and lock
-/// downgrading.
-pub unsafe trait RawRwLockUpgradeDowngrade: RawRwLockUpgrade + RawRwLockDowngrade {
-    /// Downgrades an upgradable lock to a shared lock.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an upgradable lock is held in the current context.
-    unsafe fn downgrade_upgradable(&self);
-
-    /// Downgrades an exclusive lock to an upgradable lock.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an exclusive lock is held in the current context.
-    unsafe fn downgrade_to_upgradable(&self);
-}
-
-/// Additional methods for RwLocks which support upgradable locks and locking
-/// with timeouts.
-pub unsafe trait RawRwLockUpgradeTimed: RawRwLockUpgrade + RawRwLockTimed {
-    /// Attempts to acquire an upgradable lock until a timeout is reached.
-    fn try_lock_upgradable_for(&self, timeout: Self::Duration) -> bool;
-
-    /// Attempts to acquire an upgradable lock until a timeout is reached.
-    fn try_lock_upgradable_until(&self, timeout: Self::Instant) -> bool;
-
-    /// Attempts to upgrade an upgradable lock to an exclusive lock until a
-    /// timeout is reached.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an upgradable lock is held in the current context.
-    unsafe fn try_upgrade_for(&self, timeout: Self::Duration) -> bool;
-
-    /// Attempts to upgrade an upgradable lock to an exclusive lock until a
-    /// timeout is reached.
-    ///
-    /// # Safety
-    ///
-    /// This method may only be called if an upgradable lock is held in the current context.
-    unsafe fn try_upgrade_until(&self, timeout: Self::Instant) -> bool;
-}
-
-/// A reader-writer lock
-///
-/// This type of lock allows a number of readers or at most one writer at any
-/// point in time. The write portion of this lock typically allows modification
-/// of the underlying data (exclusive access) and the read portion of this lock
-/// typically allows for read-only access (shared access).
-///
-/// The type parameter `T` represents the data that this lock protects. It is
-/// required that `T` satisfies `Send` to be shared across threads and `Sync` to
-/// allow concurrent access through readers. The RAII guards returned from the
-/// locking methods implement `Deref` (and `DerefMut` for the `write` methods)
-/// to allow access to the contained of the lock.
-pub struct RwLock<R, T: ?Sized> {
-    raw: R,
-    data: UnsafeCell<T>,
-}
-
-// Copied and modified from serde
-#[cfg(feature = "serde")]
-impl<R, T> Serialize for RwLock<R, T>
-where
-    R: RawRwLock,
-    T: Serialize + ?Sized,
-{
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        self.read().serialize(serializer)
-    }
-}
-
-#[cfg(feature = "serde")]
-impl<'de, R, T> Deserialize<'de> for RwLock<R, T>
-where
-    R: RawRwLock,
-    T: Deserialize<'de> + ?Sized,
-{
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: Deserializer<'de>,
-    {
-        Deserialize::deserialize(deserializer).map(RwLock::new)
-    }
-}
-
-unsafe impl<R: RawRwLock + Send, T: ?Sized + Send> Send for RwLock<R, T> {}
-unsafe impl<R: RawRwLock + Sync, T: ?Sized + Send + Sync> Sync for RwLock<R, T> {}
-
-impl<R: RawRwLock, T> RwLock<R, T> {
-    /// Creates a new instance of an `RwLock<T>` which is unlocked.
-    #[cfg(has_const_fn_trait_bound)]
-    #[inline]
-    pub const fn new(val: T) -> RwLock<R, T> {
-        RwLock {
-            data: UnsafeCell::new(val),
-            raw: R::INIT,
-        }
-    }
-
-    /// Creates a new instance of an `RwLock<T>` which is unlocked.
-    #[cfg(not(has_const_fn_trait_bound))]
-    #[inline]
-    pub fn new(val: T) -> RwLock<R, T> {
-        RwLock {
-            data: UnsafeCell::new(val),
-            raw: R::INIT,
-        }
-    }
-
-    /// Consumes this `RwLock`, returning the underlying data.
-    #[inline]
-    #[allow(unused_unsafe)]
-    pub fn into_inner(self) -> T {
-        unsafe { self.data.into_inner() }
-    }
-}
-
-impl<R, T> RwLock<R, T> {
-    /// Creates a new new instance of an `RwLock<T>` based on a pre-existing
-    /// `RawRwLock<T>`.
-    ///
-    /// This allows creating a `RwLock<T>` in a constant context on stable
-    /// Rust.
-    #[inline]
-    pub const fn const_new(raw_rwlock: R, val: T) -> RwLock<R, T> {
-        RwLock {
-            data: UnsafeCell::new(val),
-            raw: raw_rwlock,
-        }
-    }
-}
-
-impl<R: RawRwLock, T: ?Sized> RwLock<R, T> {
-    /// Creates a new `RwLockReadGuard` without checking if the lock is held.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the thread logically holds a read lock.
-    ///
-    /// This function does not increment the read count of the lock. Calling this function when a
-    /// guard has already been produced is undefined behaviour unless the guard was forgotten
-    /// with `mem::forget`.`
-    #[inline]
-    pub unsafe fn make_read_guard_unchecked(&self) -> RwLockReadGuard<'_, R, T> {
-        RwLockReadGuard {
-            rwlock: self,
-            marker: PhantomData,
-        }
-    }
-
-    /// Creates a new `RwLockReadGuard` without checking if the lock is held.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the thread logically holds a write lock.
-    ///
-    /// Calling this function when a guard has already been produced is undefined behaviour unless
-    /// the guard was forgotten with `mem::forget`.
-    #[inline]
-    pub unsafe fn make_write_guard_unchecked(&self) -> RwLockWriteGuard<'_, R, T> {
-        RwLockWriteGuard {
-            rwlock: self,
-            marker: PhantomData,
-        }
-    }
-
-    /// Locks this `RwLock` with shared read access, blocking the current thread
-    /// until it can be acquired.
-    ///
-    /// The calling thread will be blocked until there are no more writers which
-    /// hold the lock. There may be other readers currently inside the lock when
-    /// this method returns.
-    ///
-    /// Note that attempts to recursively acquire a read lock on a `RwLock` when
-    /// the current thread already holds one may result in a deadlock.
-    ///
-    /// Returns an RAII guard which will release this thread's shared access
-    /// once it is dropped.
-    #[inline]
-    pub fn read(&self) -> RwLockReadGuard<'_, R, T> {
-        self.raw.lock_shared();
-        // SAFETY: The lock is held, as required.
-        unsafe { self.make_read_guard_unchecked() }
-    }
-
-    /// Attempts to acquire this `RwLock` with shared read access.
-    ///
-    /// If the access could not be granted at this time, then `None` is returned.
-    /// Otherwise, an RAII guard is returned which will release the shared access
-    /// when it is dropped.
-    ///
-    /// This function does not block.
-    #[inline]
-    pub fn try_read(&self) -> Option<RwLockReadGuard<'_, R, T>> {
-        if self.raw.try_lock_shared() {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Locks this `RwLock` with exclusive write access, blocking the current
-    /// thread until it can be acquired.
-    ///
-    /// This function will not return while other writers or other readers
-    /// currently have access to the lock.
-    ///
-    /// Returns an RAII guard which will drop the write access of this `RwLock`
-    /// when dropped.
-    #[inline]
-    pub fn write(&self) -> RwLockWriteGuard<'_, R, T> {
-        self.raw.lock_exclusive();
-        // SAFETY: The lock is held, as required.
-        unsafe { self.make_write_guard_unchecked() }
-    }
-
-    /// Attempts to lock this `RwLock` with exclusive write access.
-    ///
-    /// If the lock could not be acquired at this time, then `None` is returned.
-    /// Otherwise, an RAII guard is returned which will release the lock when
-    /// it is dropped.
-    ///
-    /// This function does not block.
-    #[inline]
-    pub fn try_write(&self) -> Option<RwLockWriteGuard<'_, R, T>> {
-        if self.raw.try_lock_exclusive() {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_write_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Returns a mutable reference to the underlying data.
-    ///
-    /// Since this call borrows the `RwLock` mutably, no actual locking needs to
-    /// take place---the mutable borrow statically guarantees no locks exist.
-    #[inline]
-    pub fn get_mut(&mut self) -> &mut T {
-        unsafe { &mut *self.data.get() }
-    }
-
-    /// Checks whether this `RwLock` is currently locked in any way.
-    #[inline]
-    pub fn is_locked(&self) -> bool {
-        self.raw.is_locked()
-    }
-
-    /// Check if this `RwLock` is currently exclusively locked.
-    #[inline]
-    pub fn is_locked_exclusive(&self) -> bool {
-        self.raw.is_locked_exclusive()
-    }
-
-    /// Forcibly unlocks a read lock.
-    ///
-    /// This is useful when combined with `mem::forget` to hold a lock without
-    /// the need to maintain a `RwLockReadGuard` object alive, for example when
-    /// dealing with FFI.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the current thread logically owns a
-    /// `RwLockReadGuard` but that guard has be discarded using `mem::forget`.
-    /// Behavior is undefined if a rwlock is read-unlocked when not read-locked.
-    #[inline]
-    pub unsafe fn force_unlock_read(&self) {
-        self.raw.unlock_shared();
-    }
-
-    /// Forcibly unlocks a write lock.
-    ///
-    /// This is useful when combined with `mem::forget` to hold a lock without
-    /// the need to maintain a `RwLockWriteGuard` object alive, for example when
-    /// dealing with FFI.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the current thread logically owns a
-    /// `RwLockWriteGuard` but that guard has be discarded using `mem::forget`.
-    /// Behavior is undefined if a rwlock is write-unlocked when not write-locked.
-    #[inline]
-    pub unsafe fn force_unlock_write(&self) {
-        self.raw.unlock_exclusive();
-    }
-
-    /// Returns the underlying raw reader-writer lock object.
-    ///
-    /// Note that you will most likely need to import the `RawRwLock` trait from
-    /// `lock_api` to be able to call functions on the raw
-    /// reader-writer lock.
-    ///
-    /// # Safety
-    ///
-    /// This method is unsafe because it allows unlocking a mutex while
-    /// still holding a reference to a lock guard.
-    pub unsafe fn raw(&self) -> &R {
-        &self.raw
-    }
-
-    /// Returns a raw pointer to the underlying data.
-    ///
-    /// This is useful when combined with `mem::forget` to hold a lock without
-    /// the need to maintain a `RwLockReadGuard` or `RwLockWriteGuard` object
-    /// alive, for example when dealing with FFI.
-    ///
-    /// # Safety
-    ///
-    /// You must ensure that there are no data races when dereferencing the
-    /// returned pointer, for example if the current thread logically owns a
-    /// `RwLockReadGuard` or `RwLockWriteGuard` but that guard has been discarded
-    /// using `mem::forget`.
-    #[inline]
-    pub fn data_ptr(&self) -> *mut T {
-        self.data.get()
-    }
-
-    /// Creates a new `RwLockReadGuard` without checking if the lock is held.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the thread logically holds a read lock.
-    ///
-    /// This function does not increment the read count of the lock. Calling this function when a
-    /// guard has already been produced is undefined behaviour unless the guard was forgotten
-    /// with `mem::forget`.`
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub unsafe fn make_arc_read_guard_unchecked(self: &Arc<Self>) -> ArcRwLockReadGuard<R, T> {
-        ArcRwLockReadGuard {
-            rwlock: self.clone(),
-            marker: PhantomData,
-        }
-    }
-
-    /// Creates a new `RwLockWriteGuard` without checking if the lock is held.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the thread logically holds a write lock.
-    ///
-    /// Calling this function when a guard has already been produced is undefined behaviour unless
-    /// the guard was forgotten with `mem::forget`.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub unsafe fn make_arc_write_guard_unchecked(self: &Arc<Self>) -> ArcRwLockWriteGuard<R, T> {
-        ArcRwLockWriteGuard {
-            rwlock: self.clone(),
-            marker: PhantomData,
-        }
-    }
-
-    /// Locks this `RwLock` with read access, through an `Arc`.
-    ///
-    /// This method is similar to the `read` method; however, it requires the `RwLock` to be inside of an `Arc`
-    /// and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn read_arc(self: &Arc<Self>) -> ArcRwLockReadGuard<R, T> {
-        self.raw.lock_shared();
-        // SAFETY: locking guarantee is upheld
-        unsafe { self.make_arc_read_guard_unchecked() }
-    }
-
-    /// Attempts to lock this `RwLock` with read access, through an `Arc`.
-    ///
-    /// This method is similar to the `try_read` method; however, it requires the `RwLock` to be inside of an
-    /// `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_read_arc(self: &Arc<Self>) -> Option<ArcRwLockReadGuard<R, T>> {
-        if self.raw.try_lock_shared() {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_arc_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Locks this `RwLock` with write access, through an `Arc`.
-    ///
-    /// This method is similar to the `write` method; however, it requires the `RwLock` to be inside of an `Arc`
-    /// and the resulting write guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn write_arc(self: &Arc<Self>) -> ArcRwLockWriteGuard<R, T> {
-        self.raw.lock_exclusive();
-        // SAFETY: locking guarantee is upheld
-        unsafe { self.make_arc_write_guard_unchecked() }
-    }
-
-    /// Attempts to lock this `RwLock` with writ access, through an `Arc`.
-    ///
-    /// This method is similar to the `try_write` method; however, it requires the `RwLock` to be inside of an
-    /// `Arc` and the resulting write guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_write_arc(self: &Arc<Self>) -> Option<ArcRwLockWriteGuard<R, T>> {
-        if self.raw.try_lock_exclusive() {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_arc_write_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-}
-
-impl<R: RawRwLockFair, T: ?Sized> RwLock<R, T> {
-    /// Forcibly unlocks a read lock using a fair unlock procotol.
-    ///
-    /// This is useful when combined with `mem::forget` to hold a lock without
-    /// the need to maintain a `RwLockReadGuard` object alive, for example when
-    /// dealing with FFI.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the current thread logically owns a
-    /// `RwLockReadGuard` but that guard has be discarded using `mem::forget`.
-    /// Behavior is undefined if a rwlock is read-unlocked when not read-locked.
-    #[inline]
-    pub unsafe fn force_unlock_read_fair(&self) {
-        self.raw.unlock_shared_fair();
-    }
-
-    /// Forcibly unlocks a write lock using a fair unlock procotol.
-    ///
-    /// This is useful when combined with `mem::forget` to hold a lock without
-    /// the need to maintain a `RwLockWriteGuard` object alive, for example when
-    /// dealing with FFI.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the current thread logically owns a
-    /// `RwLockWriteGuard` but that guard has be discarded using `mem::forget`.
-    /// Behavior is undefined if a rwlock is write-unlocked when not write-locked.
-    #[inline]
-    pub unsafe fn force_unlock_write_fair(&self) {
-        self.raw.unlock_exclusive_fair();
-    }
-}
-
-impl<R: RawRwLockTimed, T: ?Sized> RwLock<R, T> {
-    /// Attempts to acquire this `RwLock` with shared read access until a timeout
-    /// is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned. Otherwise, an RAII guard is returned which will
-    /// release the shared access when it is dropped.
-    #[inline]
-    pub fn try_read_for(&self, timeout: R::Duration) -> Option<RwLockReadGuard<'_, R, T>> {
-        if self.raw.try_lock_shared_for(timeout) {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to acquire this `RwLock` with shared read access until a timeout
-    /// is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned. Otherwise, an RAII guard is returned which will
-    /// release the shared access when it is dropped.
-    #[inline]
-    pub fn try_read_until(&self, timeout: R::Instant) -> Option<RwLockReadGuard<'_, R, T>> {
-        if self.raw.try_lock_shared_until(timeout) {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to acquire this `RwLock` with exclusive write access until a
-    /// timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned. Otherwise, an RAII guard is returned which will
-    /// release the exclusive access when it is dropped.
-    #[inline]
-    pub fn try_write_for(&self, timeout: R::Duration) -> Option<RwLockWriteGuard<'_, R, T>> {
-        if self.raw.try_lock_exclusive_for(timeout) {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_write_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to acquire this `RwLock` with exclusive write access until a
-    /// timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned. Otherwise, an RAII guard is returned which will
-    /// release the exclusive access when it is dropped.
-    #[inline]
-    pub fn try_write_until(&self, timeout: R::Instant) -> Option<RwLockWriteGuard<'_, R, T>> {
-        if self.raw.try_lock_exclusive_until(timeout) {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_write_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to acquire this `RwLock` with read access until a timeout is reached, through an `Arc`.
-    ///
-    /// This method is similar to the `try_read_for` method; however, it requires the `RwLock` to be inside of an
-    /// `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_read_arc_for(
-        self: &Arc<Self>,
-        timeout: R::Duration,
-    ) -> Option<ArcRwLockReadGuard<R, T>> {
-        if self.raw.try_lock_shared_for(timeout) {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_arc_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to acquire this `RwLock` with read access until a timeout is reached, through an `Arc`.
-    ///
-    /// This method is similar to the `try_read_until` method; however, it requires the `RwLock` to be inside of
-    /// an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_read_arc_until(
-        self: &Arc<Self>,
-        timeout: R::Instant,
-    ) -> Option<ArcRwLockReadGuard<R, T>> {
-        if self.raw.try_lock_shared_until(timeout) {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_arc_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to acquire this `RwLock` with write access until a timeout is reached, through an `Arc`.
-    ///
-    /// This method is similar to the `try_write_for` method; however, it requires the `RwLock` to be inside of
-    /// an `Arc` and the resulting write guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_write_arc_for(
-        self: &Arc<Self>,
-        timeout: R::Duration,
-    ) -> Option<ArcRwLockWriteGuard<R, T>> {
-        if self.raw.try_lock_exclusive_for(timeout) {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_arc_write_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to acquire this `RwLock` with read access until a timeout is reached, through an `Arc`.
-    ///
-    /// This method is similar to the `try_write_until` method; however, it requires the `RwLock` to be inside of
-    /// an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_write_arc_until(
-        self: &Arc<Self>,
-        timeout: R::Instant,
-    ) -> Option<ArcRwLockWriteGuard<R, T>> {
-        if self.raw.try_lock_exclusive_until(timeout) {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_arc_write_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-}
-
-impl<R: RawRwLockRecursive, T: ?Sized> RwLock<R, T> {
-    /// Locks this `RwLock` with shared read access, blocking the current thread
-    /// until it can be acquired.
-    ///
-    /// The calling thread will be blocked until there are no more writers which
-    /// hold the lock. There may be other readers currently inside the lock when
-    /// this method returns.
-    ///
-    /// Unlike `read`, this method is guaranteed to succeed without blocking if
-    /// another read lock is held at the time of the call. This allows a thread
-    /// to recursively lock a `RwLock`. However using this method can cause
-    /// writers to starve since readers no longer block if a writer is waiting
-    /// for the lock.
-    ///
-    /// Returns an RAII guard which will release this thread's shared access
-    /// once it is dropped.
-    #[inline]
-    pub fn read_recursive(&self) -> RwLockReadGuard<'_, R, T> {
-        self.raw.lock_shared_recursive();
-        // SAFETY: The lock is held, as required.
-        unsafe { self.make_read_guard_unchecked() }
-    }
-
-    /// Attempts to acquire this `RwLock` with shared read access.
-    ///
-    /// If the access could not be granted at this time, then `None` is returned.
-    /// Otherwise, an RAII guard is returned which will release the shared access
-    /// when it is dropped.
-    ///
-    /// This method is guaranteed to succeed if another read lock is held at the
-    /// time of the call. See the documentation for `read_recursive` for details.
-    ///
-    /// This function does not block.
-    #[inline]
-    pub fn try_read_recursive(&self) -> Option<RwLockReadGuard<'_, R, T>> {
-        if self.raw.try_lock_shared_recursive() {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Locks this `RwLock` with shared read access, through an `Arc`.
-    ///
-    /// This method is similar to the `read_recursive` method; however, it requires the `RwLock` to be inside of
-    /// an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn read_arc_recursive(self: &Arc<Self>) -> ArcRwLockReadGuard<R, T> {
-        self.raw.lock_shared_recursive();
-        // SAFETY: locking guarantee is upheld
-        unsafe { self.make_arc_read_guard_unchecked() }
-    }
-
-    /// Attempts to lock this `RwLock` with shared read access, through an `Arc`.
-    ///
-    /// This method is similar to the `try_read_recursive` method; however, it requires the `RwLock` to be inside
-    /// of an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_read_recursive_arc(self: &Arc<Self>) -> Option<ArcRwLockReadGuard<R, T>> {
-        if self.raw.try_lock_shared_recursive() {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_arc_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-}
-
-impl<R: RawRwLockRecursiveTimed, T: ?Sized> RwLock<R, T> {
-    /// Attempts to acquire this `RwLock` with shared read access until a timeout
-    /// is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned. Otherwise, an RAII guard is returned which will
-    /// release the shared access when it is dropped.
-    ///
-    /// This method is guaranteed to succeed without blocking if another read
-    /// lock is held at the time of the call. See the documentation for
-    /// `read_recursive` for details.
-    #[inline]
-    pub fn try_read_recursive_for(
-        &self,
-        timeout: R::Duration,
-    ) -> Option<RwLockReadGuard<'_, R, T>> {
-        if self.raw.try_lock_shared_recursive_for(timeout) {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to acquire this `RwLock` with shared read access until a timeout
-    /// is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned. Otherwise, an RAII guard is returned which will
-    /// release the shared access when it is dropped.
-    #[inline]
-    pub fn try_read_recursive_until(
-        &self,
-        timeout: R::Instant,
-    ) -> Option<RwLockReadGuard<'_, R, T>> {
-        if self.raw.try_lock_shared_recursive_until(timeout) {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to lock this `RwLock` with read access until a timeout is reached, through an `Arc`.
-    ///
-    /// This method is similar to the `try_read_recursive_for` method; however, it requires the `RwLock` to be
-    /// inside of an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_read_arc_recursive_for(
-        self: &Arc<Self>,
-        timeout: R::Duration,
-    ) -> Option<ArcRwLockReadGuard<R, T>> {
-        if self.raw.try_lock_shared_recursive_for(timeout) {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_arc_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to lock this `RwLock` with read access until a timeout is reached, through an `Arc`.
-    ///
-    /// This method is similar to the `try_read_recursive_until` method; however, it requires the `RwLock` to be
-    /// inside of an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_read_arc_recursive_until(
-        self: &Arc<Self>,
-        timeout: R::Instant,
-    ) -> Option<ArcRwLockReadGuard<R, T>> {
-        if self.raw.try_lock_shared_recursive_until(timeout) {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_arc_read_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-}
-
-impl<R: RawRwLockUpgrade, T: ?Sized> RwLock<R, T> {
-    /// Creates a new `RwLockUpgradableReadGuard` without checking if the lock is held.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the thread logically holds an upgradable read lock.
-    ///
-    /// This function does not increment the read count of the lock. Calling this function when a
-    /// guard has already been produced is undefined behaviour unless the guard was forgotten
-    /// with `mem::forget`.`
-    #[inline]
-    pub unsafe fn make_upgradable_guard_unchecked(&self) -> RwLockUpgradableReadGuard<'_, R, T> {
-        RwLockUpgradableReadGuard {
-            rwlock: self,
-            marker: PhantomData,
-        }
-    }
-
-    /// Locks this `RwLock` with upgradable read access, blocking the current thread
-    /// until it can be acquired.
-    ///
-    /// The calling thread will be blocked until there are no more writers or other
-    /// upgradable reads which hold the lock. There may be other readers currently
-    /// inside the lock when this method returns.
-    ///
-    /// Returns an RAII guard which will release this thread's shared access
-    /// once it is dropped.
-    #[inline]
-    pub fn upgradable_read(&self) -> RwLockUpgradableReadGuard<'_, R, T> {
-        self.raw.lock_upgradable();
-        // SAFETY: The lock is held, as required.
-        unsafe { self.make_upgradable_guard_unchecked() }
-    }
-
-    /// Attempts to acquire this `RwLock` with upgradable read access.
-    ///
-    /// If the access could not be granted at this time, then `None` is returned.
-    /// Otherwise, an RAII guard is returned which will release the shared access
-    /// when it is dropped.
-    ///
-    /// This function does not block.
-    #[inline]
-    pub fn try_upgradable_read(&self) -> Option<RwLockUpgradableReadGuard<'_, R, T>> {
-        if self.raw.try_lock_upgradable() {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_upgradable_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Creates a new `ArcRwLockUpgradableReadGuard` without checking if the lock is held.
-    ///
-    /// # Safety
-    ///
-    /// This method must only be called if the thread logically holds an upgradable read lock.
-    ///
-    /// This function does not increment the read count of the lock. Calling this function when a
-    /// guard has already been produced is undefined behaviour unless the guard was forgotten
-    /// with `mem::forget`.`
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub unsafe fn make_upgradable_arc_guard_unchecked(
-        self: &Arc<Self>,
-    ) -> ArcRwLockUpgradableReadGuard<R, T> {
-        ArcRwLockUpgradableReadGuard {
-            rwlock: self.clone(),
-            marker: PhantomData,
-        }
-    }
-
-    /// Locks this `RwLock` with upgradable read access, through an `Arc`.
-    ///
-    /// This method is similar to the `upgradable_read` method; however, it requires the `RwLock` to be
-    /// inside of an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn upgradable_read_arc(self: &Arc<Self>) -> ArcRwLockUpgradableReadGuard<R, T> {
-        self.raw.lock_upgradable();
-        // SAFETY: locking guarantee is upheld
-        unsafe { self.make_upgradable_arc_guard_unchecked() }
-    }
-
-    /// Attempts to lock this `RwLock` with upgradable read access, through an `Arc`.
-    ///
-    /// This method is similar to the `try_upgradable_read` method; however, it requires the `RwLock` to be
-    /// inside of an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_upgradable_read_arc(self: &Arc<Self>) -> Option<ArcRwLockUpgradableReadGuard<R, T>> {
-        if self.raw.try_lock_upgradable() {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_upgradable_arc_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-}
-
-impl<R: RawRwLockUpgradeTimed, T: ?Sized> RwLock<R, T> {
-    /// Attempts to acquire this `RwLock` with upgradable read access until a timeout
-    /// is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned. Otherwise, an RAII guard is returned which will
-    /// release the shared access when it is dropped.
-    #[inline]
-    pub fn try_upgradable_read_for(
-        &self,
-        timeout: R::Duration,
-    ) -> Option<RwLockUpgradableReadGuard<'_, R, T>> {
-        if self.raw.try_lock_upgradable_for(timeout) {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_upgradable_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to acquire this `RwLock` with upgradable read access until a timeout
-    /// is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned. Otherwise, an RAII guard is returned which will
-    /// release the shared access when it is dropped.
-    #[inline]
-    pub fn try_upgradable_read_until(
-        &self,
-        timeout: R::Instant,
-    ) -> Option<RwLockUpgradableReadGuard<'_, R, T>> {
-        if self.raw.try_lock_upgradable_until(timeout) {
-            // SAFETY: The lock is held, as required.
-            Some(unsafe { self.make_upgradable_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to lock this `RwLock` with upgradable access until a timeout is reached, through an `Arc`.
-    ///
-    /// This method is similar to the `try_upgradable_read_for` method; however, it requires the `RwLock` to be
-    /// inside of an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_upgradable_read_arc_for(
-        self: &Arc<Self>,
-        timeout: R::Duration,
-    ) -> Option<ArcRwLockUpgradableReadGuard<R, T>> {
-        if self.raw.try_lock_upgradable_for(timeout) {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_upgradable_arc_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-
-    /// Attempts to lock this `RwLock` with upgradable access until a timeout is reached, through an `Arc`.
-    ///
-    /// This method is similar to the `try_upgradable_read_until` method; however, it requires the `RwLock` to be
-    /// inside of an `Arc` and the resulting read guard has no lifetime requirements.
-    #[cfg(feature = "arc_lock")]
-    #[inline]
-    pub fn try_upgradable_read_arc_until(
-        self: &Arc<Self>,
-        timeout: R::Instant,
-    ) -> Option<ArcRwLockUpgradableReadGuard<R, T>> {
-        if self.raw.try_lock_upgradable_until(timeout) {
-            // SAFETY: locking guarantee is upheld
-            Some(unsafe { self.make_upgradable_arc_guard_unchecked() })
-        } else {
-            None
-        }
-    }
-}
-
-impl<R: RawRwLock, T: ?Sized + Default> Default for RwLock<R, T> {
-    #[inline]
-    fn default() -> RwLock<R, T> {
-        RwLock::new(Default::default())
-    }
-}
-
-impl<R: RawRwLock, T> From<T> for RwLock<R, T> {
-    #[inline]
-    fn from(t: T) -> RwLock<R, T> {
-        RwLock::new(t)
-    }
-}
-
-impl<R: RawRwLock, T: ?Sized + fmt::Debug> fmt::Debug for RwLock<R, T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.try_read() {
-            Some(guard) => f.debug_struct("RwLock").field("data", &&*guard).finish(),
-            None => {
-                struct LockedPlaceholder;
-                impl fmt::Debug for LockedPlaceholder {
-                    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-                        f.write_str("<locked>")
-                    }
-                }
-
-                f.debug_struct("RwLock")
-                    .field("data", &LockedPlaceholder)
-                    .finish()
-            }
-        }
-    }
-}
-
-/// RAII structure used to release the shared read access of a lock when
-/// dropped.
-#[clippy::has_significant_drop]
-#[must_use = "if unused the RwLock will immediately unlock"]
-pub struct RwLockReadGuard<'a, R: RawRwLock, T: ?Sized> {
-    rwlock: &'a RwLock<R, T>,
-    marker: PhantomData<(&'a T, R::GuardMarker)>,
-}
-
-unsafe impl<R: RawRwLock + Sync, T: Sync + ?Sized> Sync for RwLockReadGuard<'_, R, T> {}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> RwLockReadGuard<'a, R, T> {
-    /// Returns a reference to the original reader-writer lock object.
-    pub fn rwlock(s: &Self) -> &'a RwLock<R, T> {
-        s.rwlock
-    }
-
-    /// Make a new `MappedRwLockReadGuard` for a component of the locked data.
-    ///
-    /// This operation cannot fail as the `RwLockReadGuard` passed
-    /// in already locked the data.
-    ///
-    /// This is an associated function that needs to be
-    /// used as `RwLockReadGuard::map(...)`. A method would interfere with methods of
-    /// the same name on the contents of the locked data.
-    #[inline]
-    pub fn map<U: ?Sized, F>(s: Self, f: F) -> MappedRwLockReadGuard<'a, R, U>
-    where
-        F: FnOnce(&T) -> &U,
-    {
-        let raw = &s.rwlock.raw;
-        let data = f(unsafe { &*s.rwlock.data.get() });
-        mem::forget(s);
-        MappedRwLockReadGuard {
-            raw,
-            data,
-            marker: PhantomData,
-        }
-    }
-
-    /// Attempts to make  a new `MappedRwLockReadGuard` for a component of the
-    /// locked data. Returns the original guard if the closure returns `None`.
-    ///
-    /// This operation cannot fail as the `RwLockReadGuard` passed
-    /// in already locked the data.
-    ///
-    /// This is an associated function that needs to be
-    /// used as `RwLockReadGuard::try_map(...)`. A method would interfere with methods of
-    /// the same name on the contents of the locked data.
-    #[inline]
-    pub fn try_map<U: ?Sized, F>(s: Self, f: F) -> Result<MappedRwLockReadGuard<'a, R, U>, Self>
-    where
-        F: FnOnce(&T) -> Option<&U>,
-    {
-        let raw = &s.rwlock.raw;
-        let data = match f(unsafe { &*s.rwlock.data.get() }) {
-            Some(data) => data,
-            None => return Err(s),
-        };
-        mem::forget(s);
-        Ok(MappedRwLockReadGuard {
-            raw,
-            data,
-            marker: PhantomData,
-        })
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// This is safe because `&mut` guarantees that there exist no other
-    /// references to the data protected by the `RwLock`.
-    #[inline]
-    pub fn unlocked<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.unlock_shared();
-        }
-        defer!(s.rwlock.raw.lock_shared());
-        f()
-    }
-}
-
-impl<'a, R: RawRwLockFair + 'a, T: ?Sized + 'a> RwLockReadGuard<'a, R, T> {
-    /// Unlocks the `RwLock` using a fair unlock protocol.
-    ///
-    /// By default, `RwLock` is unfair and allow the current thread to re-lock
-    /// the `RwLock` before another has the chance to acquire the lock, even if
-    /// that thread has been blocked on the `RwLock` for a long time. This is
-    /// the default because it allows much higher throughput as it avoids
-    /// forcing a context switch on every `RwLock` unlock. This can result in one
-    /// thread acquiring a `RwLock` many more times than other threads.
-    ///
-    /// However in some cases it can be beneficial to ensure fairness by forcing
-    /// the lock to pass on to a waiting thread if there is one. This is done by
-    /// using this method instead of dropping the `RwLockReadGuard` normally.
-    #[inline]
-    pub fn unlock_fair(s: Self) {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.unlock_shared_fair();
-        }
-        mem::forget(s);
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// The `RwLock` is unlocked a fair unlock protocol.
-    ///
-    /// This is safe because `&mut` guarantees that there exist no other
-    /// references to the data protected by the `RwLock`.
-    #[inline]
-    pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.unlock_shared_fair();
-        }
-        defer!(s.rwlock.raw.lock_shared());
-        f()
-    }
-
-    /// Temporarily yields the `RwLock` to a waiting thread if there is one.
-    ///
-    /// This method is functionally equivalent to calling `unlock_fair` followed
-    /// by `read`, however it can be much more efficient in the case where there
-    /// are no waiting threads.
-    #[inline]
-    pub fn bump(s: &mut Self) {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.bump_shared();
-        }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Deref for RwLockReadGuard<'a, R, T> {
-    type Target = T;
-    #[inline]
-    fn deref(&self) -> &T {
-        unsafe { &*self.rwlock.data.get() }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Drop for RwLockReadGuard<'a, R, T> {
-    #[inline]
-    fn drop(&mut self) {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            self.rwlock.raw.unlock_shared();
-        }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: fmt::Debug + ?Sized + 'a> fmt::Debug for RwLockReadGuard<'a, R, T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&**self, f)
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: fmt::Display + ?Sized + 'a> fmt::Display
-    for RwLockReadGuard<'a, R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (**self).fmt(f)
-    }
-}
-
-#[cfg(feature = "owning_ref")]
-unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> StableAddress for RwLockReadGuard<'a, R, T> {}
-
-/// An RAII rwlock guard returned by the `Arc` locking operations on `RwLock`.
-///
-/// This is similar to the `RwLockReadGuard` struct, except instead of using a reference to unlock the `RwLock`
-/// it uses an `Arc<RwLock>`. This has several advantages, most notably that it has an `'static` lifetime.
-#[cfg(feature = "arc_lock")]
-#[clippy::has_significant_drop]
-#[must_use = "if unused the RwLock will immediately unlock"]
-pub struct ArcRwLockReadGuard<R: RawRwLock, T: ?Sized> {
-    rwlock: Arc<RwLock<R, T>>,
-    marker: PhantomData<R::GuardMarker>,
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: ?Sized> ArcRwLockReadGuard<R, T> {
-    /// Returns a reference to the rwlock, contained in its `Arc`.
-    pub fn rwlock(s: &Self) -> &Arc<RwLock<R, T>> {
-        &s.rwlock
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// This is functionally identical to the `unlocked` method on [`RwLockReadGuard`].
-    #[inline]
-    pub fn unlocked<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.unlock_shared();
-        }
-        defer!(s.rwlock.raw.lock_shared());
-        f()
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockFair, T: ?Sized> ArcRwLockReadGuard<R, T> {
-    /// Unlocks the `RwLock` using a fair unlock protocol.
-    ///
-    /// This is functionally identical to the `unlock_fair` method on [`RwLockReadGuard`].
-    #[inline]
-    pub fn unlock_fair(s: Self) {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.unlock_shared_fair();
-        }
-
-        // SAFETY: ensure the Arc has its refcount decremented
-        let mut s = ManuallyDrop::new(s);
-        unsafe { ptr::drop_in_place(&mut s.rwlock) };
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// This is functionally identical to the `unlocked_fair` method on [`RwLockReadGuard`].
-    #[inline]
-    pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.unlock_shared_fair();
-        }
-        defer!(s.rwlock.raw.lock_shared());
-        f()
-    }
-
-    /// Temporarily yields the `RwLock` to a waiting thread if there is one.
-    ///
-    /// This is functionally identical to the `bump` method on [`RwLockReadGuard`].
-    #[inline]
-    pub fn bump(s: &mut Self) {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.bump_shared();
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: ?Sized> Deref for ArcRwLockReadGuard<R, T> {
-    type Target = T;
-    #[inline]
-    fn deref(&self) -> &T {
-        unsafe { &*self.rwlock.data.get() }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: ?Sized> Drop for ArcRwLockReadGuard<R, T> {
-    #[inline]
-    fn drop(&mut self) {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            self.rwlock.raw.unlock_shared();
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: fmt::Debug + ?Sized> fmt::Debug for ArcRwLockReadGuard<R, T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&**self, f)
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: fmt::Display + ?Sized> fmt::Display for ArcRwLockReadGuard<R, T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (**self).fmt(f)
-    }
-}
-
-/// RAII structure used to release the exclusive write access of a lock when
-/// dropped.
-#[clippy::has_significant_drop]
-#[must_use = "if unused the RwLock will immediately unlock"]
-pub struct RwLockWriteGuard<'a, R: RawRwLock, T: ?Sized> {
-    rwlock: &'a RwLock<R, T>,
-    marker: PhantomData<(&'a mut T, R::GuardMarker)>,
-}
-
-unsafe impl<R: RawRwLock + Sync, T: Sync + ?Sized> Sync for RwLockWriteGuard<'_, R, T> {}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> RwLockWriteGuard<'a, R, T> {
-    /// Returns a reference to the original reader-writer lock object.
-    pub fn rwlock(s: &Self) -> &'a RwLock<R, T> {
-        s.rwlock
-    }
-
-    /// Make a new `MappedRwLockWriteGuard` for a component of the locked data.
-    ///
-    /// This operation cannot fail as the `RwLockWriteGuard` passed
-    /// in already locked the data.
-    ///
-    /// This is an associated function that needs to be
-    /// used as `RwLockWriteGuard::map(...)`. A method would interfere with methods of
-    /// the same name on the contents of the locked data.
-    #[inline]
-    pub fn map<U: ?Sized, F>(s: Self, f: F) -> MappedRwLockWriteGuard<'a, R, U>
-    where
-        F: FnOnce(&mut T) -> &mut U,
-    {
-        let raw = &s.rwlock.raw;
-        let data = f(unsafe { &mut *s.rwlock.data.get() });
-        mem::forget(s);
-        MappedRwLockWriteGuard {
-            raw,
-            data,
-            marker: PhantomData,
-        }
-    }
-
-    /// Attempts to make  a new `MappedRwLockWriteGuard` for a component of the
-    /// locked data. The original guard is return if the closure returns `None`.
-    ///
-    /// This operation cannot fail as the `RwLockWriteGuard` passed
-    /// in already locked the data.
-    ///
-    /// This is an associated function that needs to be
-    /// used as `RwLockWriteGuard::try_map(...)`. A method would interfere with methods of
-    /// the same name on the contents of the locked data.
-    #[inline]
-    pub fn try_map<U: ?Sized, F>(s: Self, f: F) -> Result<MappedRwLockWriteGuard<'a, R, U>, Self>
-    where
-        F: FnOnce(&mut T) -> Option<&mut U>,
-    {
-        let raw = &s.rwlock.raw;
-        let data = match f(unsafe { &mut *s.rwlock.data.get() }) {
-            Some(data) => data,
-            None => return Err(s),
-        };
-        mem::forget(s);
-        Ok(MappedRwLockWriteGuard {
-            raw,
-            data,
-            marker: PhantomData,
-        })
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// This is safe because `&mut` guarantees that there exist no other
-    /// references to the data protected by the `RwLock`.
-    #[inline]
-    pub fn unlocked<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.unlock_exclusive();
-        }
-        defer!(s.rwlock.raw.lock_exclusive());
-        f()
-    }
-}
-
-impl<'a, R: RawRwLockDowngrade + 'a, T: ?Sized + 'a> RwLockWriteGuard<'a, R, T> {
-    /// Atomically downgrades a write lock into a read lock without allowing any
-    /// writers to take exclusive access of the lock in the meantime.
-    ///
-    /// Note that if there are any writers currently waiting to take the lock
-    /// then other readers may not be able to acquire the lock even if it was
-    /// downgraded.
-    pub fn downgrade(s: Self) -> RwLockReadGuard<'a, R, T> {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.downgrade();
-        }
-        let rwlock = s.rwlock;
-        mem::forget(s);
-        RwLockReadGuard {
-            rwlock,
-            marker: PhantomData,
-        }
-    }
-}
-
-impl<'a, R: RawRwLockUpgradeDowngrade + 'a, T: ?Sized + 'a> RwLockWriteGuard<'a, R, T> {
-    /// Atomically downgrades a write lock into an upgradable read lock without allowing any
-    /// writers to take exclusive access of the lock in the meantime.
-    ///
-    /// Note that if there are any writers currently waiting to take the lock
-    /// then other readers may not be able to acquire the lock even if it was
-    /// downgraded.
-    pub fn downgrade_to_upgradable(s: Self) -> RwLockUpgradableReadGuard<'a, R, T> {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.downgrade_to_upgradable();
-        }
-        let rwlock = s.rwlock;
-        mem::forget(s);
-        RwLockUpgradableReadGuard {
-            rwlock,
-            marker: PhantomData,
-        }
-    }
-}
-
-impl<'a, R: RawRwLockFair + 'a, T: ?Sized + 'a> RwLockWriteGuard<'a, R, T> {
-    /// Unlocks the `RwLock` using a fair unlock protocol.
-    ///
-    /// By default, `RwLock` is unfair and allow the current thread to re-lock
-    /// the `RwLock` before another has the chance to acquire the lock, even if
-    /// that thread has been blocked on the `RwLock` for a long time. This is
-    /// the default because it allows much higher throughput as it avoids
-    /// forcing a context switch on every `RwLock` unlock. This can result in one
-    /// thread acquiring a `RwLock` many more times than other threads.
-    ///
-    /// However in some cases it can be beneficial to ensure fairness by forcing
-    /// the lock to pass on to a waiting thread if there is one. This is done by
-    /// using this method instead of dropping the `RwLockWriteGuard` normally.
-    #[inline]
-    pub fn unlock_fair(s: Self) {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.unlock_exclusive_fair();
-        }
-        mem::forget(s);
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// The `RwLock` is unlocked a fair unlock protocol.
-    ///
-    /// This is safe because `&mut` guarantees that there exist no other
-    /// references to the data protected by the `RwLock`.
-    #[inline]
-    pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.unlock_exclusive_fair();
-        }
-        defer!(s.rwlock.raw.lock_exclusive());
-        f()
-    }
-
-    /// Temporarily yields the `RwLock` to a waiting thread if there is one.
-    ///
-    /// This method is functionally equivalent to calling `unlock_fair` followed
-    /// by `write`, however it can be much more efficient in the case where there
-    /// are no waiting threads.
-    #[inline]
-    pub fn bump(s: &mut Self) {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.bump_exclusive();
-        }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Deref for RwLockWriteGuard<'a, R, T> {
-    type Target = T;
-    #[inline]
-    fn deref(&self) -> &T {
-        unsafe { &*self.rwlock.data.get() }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> DerefMut for RwLockWriteGuard<'a, R, T> {
-    #[inline]
-    fn deref_mut(&mut self) -> &mut T {
-        unsafe { &mut *self.rwlock.data.get() }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Drop for RwLockWriteGuard<'a, R, T> {
-    #[inline]
-    fn drop(&mut self) {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            self.rwlock.raw.unlock_exclusive();
-        }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: fmt::Debug + ?Sized + 'a> fmt::Debug for RwLockWriteGuard<'a, R, T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&**self, f)
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: fmt::Display + ?Sized + 'a> fmt::Display
-    for RwLockWriteGuard<'a, R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (**self).fmt(f)
-    }
-}
-
-#[cfg(feature = "owning_ref")]
-unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> StableAddress for RwLockWriteGuard<'a, R, T> {}
-
-/// An RAII rwlock guard returned by the `Arc` locking operations on `RwLock`.
-/// This is similar to the `RwLockWriteGuard` struct, except instead of using a reference to unlock the `RwLock`
-/// it uses an `Arc<RwLock>`. This has several advantages, most notably that it has an `'static` lifetime.
-#[cfg(feature = "arc_lock")]
-#[clippy::has_significant_drop]
-#[must_use = "if unused the RwLock will immediately unlock"]
-pub struct ArcRwLockWriteGuard<R: RawRwLock, T: ?Sized> {
-    rwlock: Arc<RwLock<R, T>>,
-    marker: PhantomData<R::GuardMarker>,
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: ?Sized> ArcRwLockWriteGuard<R, T> {
-    /// Returns a reference to the rwlock, contained in its `Arc`.
-    pub fn rwlock(s: &Self) -> &Arc<RwLock<R, T>> {
-        &s.rwlock
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// This is functionally equivalent to the `unlocked` method on [`RwLockWriteGuard`].
-    #[inline]
-    pub fn unlocked<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockWriteGuard always holds a shared lock.
-        unsafe {
-            s.rwlock.raw.unlock_exclusive();
-        }
-        defer!(s.rwlock.raw.lock_exclusive());
-        f()
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockDowngrade, T: ?Sized> ArcRwLockWriteGuard<R, T> {
-    /// Atomically downgrades a write lock into a read lock without allowing any
-    /// writers to take exclusive access of the lock in the meantime.
-    ///
-    /// This is functionally equivalent to the `downgrade` method on [`RwLockWriteGuard`].
-    pub fn downgrade(s: Self) -> ArcRwLockReadGuard<R, T> {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.downgrade();
-        }
-
-        // SAFETY: prevent the arc's refcount from changing using ManuallyDrop and ptr::read
-        let s = ManuallyDrop::new(s);
-        let rwlock = unsafe { ptr::read(&s.rwlock) };
-
-        ArcRwLockReadGuard {
-            rwlock,
-            marker: PhantomData,
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgradeDowngrade, T: ?Sized> ArcRwLockWriteGuard<R, T> {
-    /// Atomically downgrades a write lock into an upgradable read lock without allowing any
-    /// writers to take exclusive access of the lock in the meantime.
-    ///
-    /// This is functionally identical to the `downgrade_to_upgradable` method on [`RwLockWriteGuard`].
-    pub fn downgrade_to_upgradable(s: Self) -> ArcRwLockUpgradableReadGuard<R, T> {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.downgrade_to_upgradable();
-        }
-
-        // SAFETY: same as above
-        let s = ManuallyDrop::new(s);
-        let rwlock = unsafe { ptr::read(&s.rwlock) };
-
-        ArcRwLockUpgradableReadGuard {
-            rwlock,
-            marker: PhantomData,
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockFair, T: ?Sized> ArcRwLockWriteGuard<R, T> {
-    /// Unlocks the `RwLock` using a fair unlock protocol.
-    ///
-    /// This is functionally equivalent to the `unlock_fair` method on [`RwLockWriteGuard`].
-    #[inline]
-    pub fn unlock_fair(s: Self) {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.unlock_exclusive_fair();
-        }
-
-        // SAFETY: prevent the Arc from leaking memory
-        let mut s = ManuallyDrop::new(s);
-        unsafe { ptr::drop_in_place(&mut s.rwlock) };
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// This is functionally equivalent to the `unlocked_fair` method on [`RwLockWriteGuard`].
-    #[inline]
-    pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.unlock_exclusive_fair();
-        }
-        defer!(s.rwlock.raw.lock_exclusive());
-        f()
-    }
-
-    /// Temporarily yields the `RwLock` to a waiting thread if there is one.
-    ///
-    /// This method is functionally equivalent to the `bump` method on [`RwLockWriteGuard`].
-    #[inline]
-    pub fn bump(s: &mut Self) {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.rwlock.raw.bump_exclusive();
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: ?Sized> Deref for ArcRwLockWriteGuard<R, T> {
-    type Target = T;
-    #[inline]
-    fn deref(&self) -> &T {
-        unsafe { &*self.rwlock.data.get() }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: ?Sized> DerefMut for ArcRwLockWriteGuard<R, T> {
-    #[inline]
-    fn deref_mut(&mut self) -> &mut T {
-        unsafe { &mut *self.rwlock.data.get() }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: ?Sized> Drop for ArcRwLockWriteGuard<R, T> {
-    #[inline]
-    fn drop(&mut self) {
-        // Safety: An RwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            self.rwlock.raw.unlock_exclusive();
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: fmt::Debug + ?Sized> fmt::Debug for ArcRwLockWriteGuard<R, T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&**self, f)
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLock, T: fmt::Display + ?Sized> fmt::Display for ArcRwLockWriteGuard<R, T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (**self).fmt(f)
-    }
-}
-
-/// RAII structure used to release the upgradable read access of a lock when
-/// dropped.
-#[clippy::has_significant_drop]
-#[must_use = "if unused the RwLock will immediately unlock"]
-pub struct RwLockUpgradableReadGuard<'a, R: RawRwLockUpgrade, T: ?Sized> {
-    rwlock: &'a RwLock<R, T>,
-    marker: PhantomData<(&'a T, R::GuardMarker)>,
-}
-
-unsafe impl<'a, R: RawRwLockUpgrade + 'a, T: ?Sized + Sync + 'a> Sync
-    for RwLockUpgradableReadGuard<'a, R, T>
-{
-}
-
-impl<'a, R: RawRwLockUpgrade + 'a, T: ?Sized + 'a> RwLockUpgradableReadGuard<'a, R, T> {
-    /// Returns a reference to the original reader-writer lock object.
-    pub fn rwlock(s: &Self) -> &'a RwLock<R, T> {
-        s.rwlock
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// This is safe because `&mut` guarantees that there exist no other
-    /// references to the data protected by the `RwLock`.
-    #[inline]
-    pub fn unlocked<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.unlock_upgradable();
-        }
-        defer!(s.rwlock.raw.lock_upgradable());
-        f()
-    }
-
-    /// Atomically upgrades an upgradable read lock lock into an exclusive write lock,
-    /// blocking the current thread until it can be acquired.
-    pub fn upgrade(s: Self) -> RwLockWriteGuard<'a, R, T> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.upgrade();
-        }
-        let rwlock = s.rwlock;
-        mem::forget(s);
-        RwLockWriteGuard {
-            rwlock,
-            marker: PhantomData,
-        }
-    }
-
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive write lock.
-    ///
-    /// If the access could not be granted at this time, then the current guard is returned.
-    pub fn try_upgrade(s: Self) -> Result<RwLockWriteGuard<'a, R, T>, Self> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        if unsafe { s.rwlock.raw.try_upgrade() } {
-            let rwlock = s.rwlock;
-            mem::forget(s);
-            Ok(RwLockWriteGuard {
-                rwlock,
-                marker: PhantomData,
-            })
-        } else {
-            Err(s)
-        }
-    }
-}
-
-impl<'a, R: RawRwLockUpgradeFair + 'a, T: ?Sized + 'a> RwLockUpgradableReadGuard<'a, R, T> {
-    /// Unlocks the `RwLock` using a fair unlock protocol.
-    ///
-    /// By default, `RwLock` is unfair and allow the current thread to re-lock
-    /// the `RwLock` before another has the chance to acquire the lock, even if
-    /// that thread has been blocked on the `RwLock` for a long time. This is
-    /// the default because it allows much higher throughput as it avoids
-    /// forcing a context switch on every `RwLock` unlock. This can result in one
-    /// thread acquiring a `RwLock` many more times than other threads.
-    ///
-    /// However in some cases it can be beneficial to ensure fairness by forcing
-    /// the lock to pass on to a waiting thread if there is one. This is done by
-    /// using this method instead of dropping the `RwLockUpgradableReadGuard` normally.
-    #[inline]
-    pub fn unlock_fair(s: Self) {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.unlock_upgradable_fair();
-        }
-        mem::forget(s);
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// The `RwLock` is unlocked a fair unlock protocol.
-    ///
-    /// This is safe because `&mut` guarantees that there exist no other
-    /// references to the data protected by the `RwLock`.
-    #[inline]
-    pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.unlock_upgradable_fair();
-        }
-        defer!(s.rwlock.raw.lock_upgradable());
-        f()
-    }
-
-    /// Temporarily yields the `RwLock` to a waiting thread if there is one.
-    ///
-    /// This method is functionally equivalent to calling `unlock_fair` followed
-    /// by `upgradable_read`, however it can be much more efficient in the case where there
-    /// are no waiting threads.
-    #[inline]
-    pub fn bump(s: &mut Self) {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.bump_upgradable();
-        }
-    }
-}
-
-impl<'a, R: RawRwLockUpgradeDowngrade + 'a, T: ?Sized + 'a> RwLockUpgradableReadGuard<'a, R, T> {
-    /// Atomically downgrades an upgradable read lock lock into a shared read lock
-    /// without allowing any writers to take exclusive access of the lock in the
-    /// meantime.
-    ///
-    /// Note that if there are any writers currently waiting to take the lock
-    /// then other readers may not be able to acquire the lock even if it was
-    /// downgraded.
-    pub fn downgrade(s: Self) -> RwLockReadGuard<'a, R, T> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.downgrade_upgradable();
-        }
-        let rwlock = s.rwlock;
-        mem::forget(s);
-        RwLockReadGuard {
-            rwlock,
-            marker: PhantomData,
-        }
-    }
-
-    /// First, atomically upgrades an upgradable read lock lock into an exclusive write lock,
-    /// blocking the current thread until it can be acquired.
-    ///
-    /// Then, calls the provided closure with an exclusive reference to the lock's data.
-    ///
-    /// Finally, atomically downgrades the lock back to an upgradable read lock.
-    /// The closure's return value is wrapped in `Some` and returned.
-    ///
-    /// This function only requires a mutable reference to the guard, unlike
-    /// `upgrade` which takes the guard by value.
-    pub fn with_upgraded<Ret, F: FnOnce(&mut T) -> Ret>(&mut self, f: F) -> Ret {
-        unsafe {
-            self.rwlock.raw.upgrade();
-        }
-
-        // Safety: We just upgraded the lock, so we have mutable access to the data.
-        // This will restore the state the lock was in at the start of the function.
-        defer!(unsafe { self.rwlock.raw.downgrade_to_upgradable() });
-
-        // Safety: We upgraded the lock, so we have mutable access to the data.
-        // When this function returns, whether by drop or panic,
-        // the drop guard will downgrade it back to an upgradeable lock.
-        f(unsafe { &mut *self.rwlock.data.get() })
-    }
-
-    /// First, tries to atomically upgrade an upgradable read lock into an exclusive write lock.
-    ///
-    /// If the access could not be granted at this time, then `None` is returned.
-    ///
-    /// Otherwise, calls the provided closure with an exclusive reference to the lock's data,
-    /// and finally downgrades the lock back to an upgradable read lock.
-    /// The closure's return value is wrapped in `Some` and returned.
-    ///
-    /// This function only requires a mutable reference to the guard, unlike
-    /// `try_upgrade` which takes the guard by value.
-    pub fn try_with_upgraded<Ret, F: FnOnce(&mut T) -> Ret>(&mut self, f: F) -> Option<Ret> {
-        if unsafe { self.rwlock.raw.try_upgrade() } {
-            // Safety: We just upgraded the lock, so we have mutable access to the data.
-            // This will restore the state the lock was in at the start of the function.
-            defer!(unsafe { self.rwlock.raw.downgrade_to_upgradable() });
-
-            // Safety: We upgraded the lock, so we have mutable access to the data.
-            // When this function returns, whether by drop or panic,
-            // the drop guard will downgrade it back to an upgradeable lock.
-            Some(f(unsafe { &mut *self.rwlock.data.get() }))
-        } else {
-            None
-        }
-    }
-}
-
-impl<'a, R: RawRwLockUpgradeTimed + 'a, T: ?Sized + 'a> RwLockUpgradableReadGuard<'a, R, T> {
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive
-    /// write lock, until a timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// the current guard is returned.
-    pub fn try_upgrade_for(
-        s: Self,
-        timeout: R::Duration,
-    ) -> Result<RwLockWriteGuard<'a, R, T>, Self> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        if unsafe { s.rwlock.raw.try_upgrade_for(timeout) } {
-            let rwlock = s.rwlock;
-            mem::forget(s);
-            Ok(RwLockWriteGuard {
-                rwlock,
-                marker: PhantomData,
-            })
-        } else {
-            Err(s)
-        }
-    }
-
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive
-    /// write lock, until a timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// the current guard is returned.
-    #[inline]
-    pub fn try_upgrade_until(
-        s: Self,
-        timeout: R::Instant,
-    ) -> Result<RwLockWriteGuard<'a, R, T>, Self> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        if unsafe { s.rwlock.raw.try_upgrade_until(timeout) } {
-            let rwlock = s.rwlock;
-            mem::forget(s);
-            Ok(RwLockWriteGuard {
-                rwlock,
-                marker: PhantomData,
-            })
-        } else {
-            Err(s)
-        }
-    }
-}
-
-impl<'a, R: RawRwLockUpgradeTimed + RawRwLockUpgradeDowngrade + 'a, T: ?Sized + 'a>
-    RwLockUpgradableReadGuard<'a, R, T>
-{
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive
-    /// write lock, until a timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned.
-    ///
-    /// Otherwise, calls the provided closure with an exclusive reference to the lock's data,
-    /// and finally downgrades the lock back to an upgradable read lock.
-    /// The closure's return value is wrapped in `Some` and returned.
-    ///
-    /// This function only requires a mutable reference to the guard, unlike
-    /// `try_upgrade_for` which takes the guard by value.
-    pub fn try_with_upgraded_for<Ret, F: FnOnce(&mut T) -> Ret>(
-        &mut self,
-        timeout: R::Duration,
-        f: F,
-    ) -> Option<Ret> {
-        if unsafe { self.rwlock.raw.try_upgrade_for(timeout) } {
-            // Safety: We just upgraded the lock, so we have mutable access to the data.
-            // This will restore the state the lock was in at the start of the function.
-            defer!(unsafe { self.rwlock.raw.downgrade_upgradable() });
-
-            // Safety: We upgraded the lock, so we have mutable access to the data.
-            // When this function returns, whether by drop or panic,
-            // the drop guard will downgrade it back to an upgradeable lock.
-            Some(f(unsafe { &mut *self.rwlock.data.get() }))
-        } else {
-            None
-        }
-    }
-
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive
-    /// write lock, until a timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned.
-    ///
-    /// Otherwise, calls the provided closure with an exclusive reference to the lock's data,
-    /// and finally downgrades the lock back to an upgradable read lock.
-    /// The closure's return value is wrapped in `Some` and returned.
-    ///
-    /// This function only requires a mutable reference to the guard, unlike
-    /// `try_upgrade_until` which takes the guard by value.
-    pub fn try_with_upgraded_until<Ret, F: FnOnce(&mut T) -> Ret>(
-        &mut self,
-        timeout: R::Instant,
-        f: F,
-    ) -> Option<Ret> {
-        if unsafe { self.rwlock.raw.try_upgrade_until(timeout) } {
-            // Safety: We just upgraded the lock, so we have mutable access to the data.
-            // This will restore the state the lock was in at the start of the function.
-            defer!(unsafe { self.rwlock.raw.downgrade_upgradable() });
-
-            // Safety: We upgraded the lock, so we have mutable access to the data.
-            // When this function returns, whether by drop or panic,
-            // the drop guard will downgrade it back to an upgradeable lock.
-            Some(f(unsafe { &mut *self.rwlock.data.get() }))
-        } else {
-            None
-        }
-    }
-}
-
-impl<'a, R: RawRwLockUpgrade + 'a, T: ?Sized + 'a> Deref for RwLockUpgradableReadGuard<'a, R, T> {
-    type Target = T;
-    #[inline]
-    fn deref(&self) -> &T {
-        unsafe { &*self.rwlock.data.get() }
-    }
-}
-
-impl<'a, R: RawRwLockUpgrade + 'a, T: ?Sized + 'a> Drop for RwLockUpgradableReadGuard<'a, R, T> {
-    #[inline]
-    fn drop(&mut self) {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            self.rwlock.raw.unlock_upgradable();
-        }
-    }
-}
-
-impl<'a, R: RawRwLockUpgrade + 'a, T: fmt::Debug + ?Sized + 'a> fmt::Debug
-    for RwLockUpgradableReadGuard<'a, R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&**self, f)
-    }
-}
-
-impl<'a, R: RawRwLockUpgrade + 'a, T: fmt::Display + ?Sized + 'a> fmt::Display
-    for RwLockUpgradableReadGuard<'a, R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (**self).fmt(f)
-    }
-}
-
-#[cfg(feature = "owning_ref")]
-unsafe impl<'a, R: RawRwLockUpgrade + 'a, T: ?Sized + 'a> StableAddress
-    for RwLockUpgradableReadGuard<'a, R, T>
-{
-}
-
-/// An RAII rwlock guard returned by the `Arc` locking operations on `RwLock`.
-/// This is similar to the `RwLockUpgradableReadGuard` struct, except instead of using a reference to unlock the
-/// `RwLock` it uses an `Arc<RwLock>`. This has several advantages, most notably that it has an `'static`
-/// lifetime.
-#[cfg(feature = "arc_lock")]
-#[clippy::has_significant_drop]
-#[must_use = "if unused the RwLock will immediately unlock"]
-pub struct ArcRwLockUpgradableReadGuard<R: RawRwLockUpgrade, T: ?Sized> {
-    rwlock: Arc<RwLock<R, T>>,
-    marker: PhantomData<R::GuardMarker>,
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgrade, T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> {
-    /// Returns a reference to the rwlock, contained in its original `Arc`.
-    pub fn rwlock(s: &Self) -> &Arc<RwLock<R, T>> {
-        &s.rwlock
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// This is functionally identical to the `unlocked` method on [`RwLockUpgradableReadGuard`].
-    #[inline]
-    pub fn unlocked<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.unlock_upgradable();
-        }
-        defer!(s.rwlock.raw.lock_upgradable());
-        f()
-    }
-
-    /// Atomically upgrades an upgradable read lock lock into an exclusive write lock,
-    /// blocking the current thread until it can be acquired.
-    pub fn upgrade(s: Self) -> ArcRwLockWriteGuard<R, T> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.upgrade();
-        }
-
-        // SAFETY: avoid incrementing or decrementing the refcount using ManuallyDrop and reading the Arc out
-        //         of the struct
-        let s = ManuallyDrop::new(s);
-        let rwlock = unsafe { ptr::read(&s.rwlock) };
-
-        ArcRwLockWriteGuard {
-            rwlock,
-            marker: PhantomData,
-        }
-    }
-
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive write lock.
-    ///
-    /// If the access could not be granted at this time, then the current guard is returned.
-    pub fn try_upgrade(s: Self) -> Result<ArcRwLockWriteGuard<R, T>, Self> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        if unsafe { s.rwlock.raw.try_upgrade() } {
-            // SAFETY: same as above
-            let s = ManuallyDrop::new(s);
-            let rwlock = unsafe { ptr::read(&s.rwlock) };
-
-            Ok(ArcRwLockWriteGuard {
-                rwlock,
-                marker: PhantomData,
-            })
-        } else {
-            Err(s)
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgradeFair, T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> {
-    /// Unlocks the `RwLock` using a fair unlock protocol.
-    ///
-    /// This is functionally identical to the `unlock_fair` method on [`RwLockUpgradableReadGuard`].
-    #[inline]
-    pub fn unlock_fair(s: Self) {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.unlock_upgradable_fair();
-        }
-
-        // SAFETY: make sure we decrement the refcount properly
-        let mut s = ManuallyDrop::new(s);
-        unsafe { ptr::drop_in_place(&mut s.rwlock) };
-    }
-
-    /// Temporarily unlocks the `RwLock` to execute the given function.
-    ///
-    /// This is functionally equivalent to the `unlocked_fair` method on [`RwLockUpgradableReadGuard`].
-    #[inline]
-    pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U
-    where
-        F: FnOnce() -> U,
-    {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.unlock_upgradable_fair();
-        }
-        defer!(s.rwlock.raw.lock_upgradable());
-        f()
-    }
-
-    /// Temporarily yields the `RwLock` to a waiting thread if there is one.
-    ///
-    /// This method is functionally equivalent to calling `bump` on [`RwLockUpgradableReadGuard`].
-    #[inline]
-    pub fn bump(s: &mut Self) {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.bump_upgradable();
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgradeDowngrade, T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> {
-    /// Atomically downgrades an upgradable read lock lock into a shared read lock
-    /// without allowing any writers to take exclusive access of the lock in the
-    /// meantime.
-    ///
-    /// Note that if there are any writers currently waiting to take the lock
-    /// then other readers may not be able to acquire the lock even if it was
-    /// downgraded.
-    pub fn downgrade(s: Self) -> ArcRwLockReadGuard<R, T> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            s.rwlock.raw.downgrade_upgradable();
-        }
-
-        // SAFETY: use ManuallyDrop and ptr::read to ensure the refcount is not changed
-        let s = ManuallyDrop::new(s);
-        let rwlock = unsafe { ptr::read(&s.rwlock) };
-
-        ArcRwLockReadGuard {
-            rwlock,
-            marker: PhantomData,
-        }
-    }
-
-    /// First, atomically upgrades an upgradable read lock lock into an exclusive write lock,
-    /// blocking the current thread until it can be acquired.
-    ///
-    /// Then, calls the provided closure with an exclusive reference to the lock's data.
-    ///
-    /// Finally, atomically downgrades the lock back to an upgradable read lock.
-    /// The closure's return value is returned.
-    ///
-    /// This function only requires a mutable reference to the guard, unlike
-    /// `upgrade` which takes the guard by value.
-    pub fn with_upgraded<Ret, F: FnOnce(&mut T) -> Ret>(&mut self, f: F) -> Ret {
-        unsafe {
-            self.rwlock.raw.upgrade();
-        }
-
-        // Safety: We just upgraded the lock, so we have mutable access to the data.
-        // This will restore the state the lock was in at the start of the function.
-        defer!(unsafe { self.rwlock.raw.downgrade_upgradable() });
-
-        // Safety: We upgraded the lock, so we have mutable access to the data.
-        // When this function returns, whether by drop or panic,
-        // the drop guard will downgrade it back to an upgradeable lock.
-        f(unsafe { &mut *self.rwlock.data.get() })
-    }
-
-    /// First, tries to atomically upgrade an upgradable read lock into an exclusive write lock.
-    ///
-    /// If the access could not be granted at this time, then `None` is returned.
-    ///
-    /// Otherwise, calls the provided closure with an exclusive reference to the lock's data,
-    /// and finally downgrades the lock back to an upgradable read lock.
-    /// The closure's return value is wrapped in `Some` and returned.
-    ///
-    /// This function only requires a mutable reference to the guard, unlike
-    /// `try_upgrade` which takes the guard by value.
-    pub fn try_with_upgraded<Ret, F: FnOnce(&mut T) -> Ret>(&mut self, f: F) -> Option<Ret> {
-        if unsafe { self.rwlock.raw.try_upgrade() } {
-            // Safety: We just upgraded the lock, so we have mutable access to the data.
-            // This will restore the state the lock was in at the start of the function.
-            defer!(unsafe { self.rwlock.raw.downgrade_upgradable() });
-
-            // Safety: We upgraded the lock, so we have mutable access to the data.
-            // When this function returns, whether by drop or panic,
-            // the drop guard will downgrade it back to an upgradeable lock.
-            Some(f(unsafe { &mut *self.rwlock.data.get() }))
-        } else {
-            None
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgradeTimed, T: ?Sized> ArcRwLockUpgradableReadGuard<R, T> {
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive
-    /// write lock, until a timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// the current guard is returned.
-    pub fn try_upgrade_for(
-        s: Self,
-        timeout: R::Duration,
-    ) -> Result<ArcRwLockWriteGuard<R, T>, Self> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        if unsafe { s.rwlock.raw.try_upgrade_for(timeout) } {
-            // SAFETY: same as above
-            let s = ManuallyDrop::new(s);
-            let rwlock = unsafe { ptr::read(&s.rwlock) };
-
-            Ok(ArcRwLockWriteGuard {
-                rwlock,
-                marker: PhantomData,
-            })
-        } else {
-            Err(s)
-        }
-    }
-
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive
-    /// write lock, until a timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// the current guard is returned.
-    #[inline]
-    pub fn try_upgrade_until(
-        s: Self,
-        timeout: R::Instant,
-    ) -> Result<ArcRwLockWriteGuard<R, T>, Self> {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        if unsafe { s.rwlock.raw.try_upgrade_until(timeout) } {
-            // SAFETY: same as above
-            let s = ManuallyDrop::new(s);
-            let rwlock = unsafe { ptr::read(&s.rwlock) };
-
-            Ok(ArcRwLockWriteGuard {
-                rwlock,
-                marker: PhantomData,
-            })
-        } else {
-            Err(s)
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgradeTimed + RawRwLockUpgradeDowngrade, T: ?Sized>
-    ArcRwLockUpgradableReadGuard<R, T>
-{
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive
-    /// write lock, until a timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned.
-    ///
-    /// Otherwise, calls the provided closure with an exclusive reference to the lock's data,
-    /// and finally downgrades the lock back to an upgradable read lock.
-    /// The closure's return value is wrapped in `Some` and returned.
-    ///
-    /// This function only requires a mutable reference to the guard, unlike
-    /// `try_upgrade_for` which takes the guard by value.
-    pub fn try_with_upgraded_for<Ret, F: FnOnce(&mut T) -> Ret>(
-        &mut self,
-        timeout: R::Duration,
-        f: F,
-    ) -> Option<Ret> {
-        if unsafe { self.rwlock.raw.try_upgrade_for(timeout) } {
-            // Safety: We just upgraded the lock, so we have mutable access to the data.
-            // This will restore the state the lock was in at the start of the function.
-            defer!(unsafe { self.rwlock.raw.downgrade_upgradable() });
-
-            // Safety: We upgraded the lock, so we have mutable access to the data.
-            // When this function returns, whether by drop or panic,
-            // the drop guard will downgrade it back to an upgradeable lock.
-            Some(f(unsafe { &mut *self.rwlock.data.get() }))
-        } else {
-            None
-        }
-    }
-
-    /// Tries to atomically upgrade an upgradable read lock into an exclusive
-    /// write lock, until a timeout is reached.
-    ///
-    /// If the access could not be granted before the timeout expires, then
-    /// `None` is returned.
-    ///
-    /// Otherwise, calls the provided closure with an exclusive reference to the lock's data,
-    /// and finally downgrades the lock back to an upgradable read lock.
-    /// The closure's return value is wrapped in `Some` and returned.
-    ///
-    /// This function only requires a mutable reference to the guard, unlike
-    /// `try_upgrade_until` which takes the guard by value.
-    pub fn try_with_upgraded_until<Ret, F: FnOnce(&mut T) -> Ret>(
-        &mut self,
-        timeout: R::Instant,
-        f: F,
-    ) -> Option<Ret> {
-        if unsafe { self.rwlock.raw.try_upgrade_until(timeout) } {
-            // Safety: We just upgraded the lock, so we have mutable access to the data.
-            // This will restore the state the lock was in at the start of the function.
-            defer!(unsafe { self.rwlock.raw.downgrade_upgradable() });
-
-            // Safety: We upgraded the lock, so we have mutable access to the data.
-            // When this function returns, whether by drop or panic,
-            // the drop guard will downgrade it back to an upgradeable lock.
-            Some(f(unsafe { &mut *self.rwlock.data.get() }))
-        } else {
-            None
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgrade, T: ?Sized> Deref for ArcRwLockUpgradableReadGuard<R, T> {
-    type Target = T;
-    #[inline]
-    fn deref(&self) -> &T {
-        unsafe { &*self.rwlock.data.get() }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgrade, T: ?Sized> Drop for ArcRwLockUpgradableReadGuard<R, T> {
-    #[inline]
-    fn drop(&mut self) {
-        // Safety: An RwLockUpgradableReadGuard always holds an upgradable lock.
-        unsafe {
-            self.rwlock.raw.unlock_upgradable();
-        }
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgrade, T: fmt::Debug + ?Sized> fmt::Debug
-    for ArcRwLockUpgradableReadGuard<R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&**self, f)
-    }
-}
-
-#[cfg(feature = "arc_lock")]
-impl<R: RawRwLockUpgrade, T: fmt::Display + ?Sized> fmt::Display
-    for ArcRwLockUpgradableReadGuard<R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (**self).fmt(f)
-    }
-}
-
-/// An RAII read lock guard returned by `RwLockReadGuard::map`, which can point to a
-/// subfield of the protected data.
-///
-/// The main difference between `MappedRwLockReadGuard` and `RwLockReadGuard` is that the
-/// former doesn't support temporarily unlocking and re-locking, since that
-/// could introduce soundness issues if the locked object is modified by another
-/// thread.
-#[clippy::has_significant_drop]
-#[must_use = "if unused the RwLock will immediately unlock"]
-pub struct MappedRwLockReadGuard<'a, R: RawRwLock, T: ?Sized> {
-    raw: &'a R,
-    data: *const T,
-    marker: PhantomData<&'a T>,
-}
-
-unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + Sync + 'a> Sync for MappedRwLockReadGuard<'a, R, T> {}
-unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + Sync + 'a> Send for MappedRwLockReadGuard<'a, R, T> where
-    R::GuardMarker: Send
-{
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> MappedRwLockReadGuard<'a, R, T> {
-    /// Make a new `MappedRwLockReadGuard` for a component of the locked data.
-    ///
-    /// This operation cannot fail as the `MappedRwLockReadGuard` passed
-    /// in already locked the data.
-    ///
-    /// This is an associated function that needs to be
-    /// used as `MappedRwLockReadGuard::map(...)`. A method would interfere with methods of
-    /// the same name on the contents of the locked data.
-    #[inline]
-    pub fn map<U: ?Sized, F>(s: Self, f: F) -> MappedRwLockReadGuard<'a, R, U>
-    where
-        F: FnOnce(&T) -> &U,
-    {
-        let raw = s.raw;
-        let data = f(unsafe { &*s.data });
-        mem::forget(s);
-        MappedRwLockReadGuard {
-            raw,
-            data,
-            marker: PhantomData,
-        }
-    }
-
-    /// Attempts to make  a new `MappedRwLockReadGuard` for a component of the
-    /// locked data. The original guard is return if the closure returns `None`.
-    ///
-    /// This operation cannot fail as the `MappedRwLockReadGuard` passed
-    /// in already locked the data.
-    ///
-    /// This is an associated function that needs to be
-    /// used as `MappedRwLockReadGuard::try_map(...)`. A method would interfere with methods of
-    /// the same name on the contents of the locked data.
-    #[inline]
-    pub fn try_map<U: ?Sized, F>(s: Self, f: F) -> Result<MappedRwLockReadGuard<'a, R, U>, Self>
-    where
-        F: FnOnce(&T) -> Option<&U>,
-    {
-        let raw = s.raw;
-        let data = match f(unsafe { &*s.data }) {
-            Some(data) => data,
-            None => return Err(s),
-        };
-        mem::forget(s);
-        Ok(MappedRwLockReadGuard {
-            raw,
-            data,
-            marker: PhantomData,
-        })
-    }
-}
-
-impl<'a, R: RawRwLockFair + 'a, T: ?Sized + 'a> MappedRwLockReadGuard<'a, R, T> {
-    /// Unlocks the `RwLock` using a fair unlock protocol.
-    ///
-    /// By default, `RwLock` is unfair and allow the current thread to re-lock
-    /// the `RwLock` before another has the chance to acquire the lock, even if
-    /// that thread has been blocked on the `RwLock` for a long time. This is
-    /// the default because it allows much higher throughput as it avoids
-    /// forcing a context switch on every `RwLock` unlock. This can result in one
-    /// thread acquiring a `RwLock` many more times than other threads.
-    ///
-    /// However in some cases it can be beneficial to ensure fairness by forcing
-    /// the lock to pass on to a waiting thread if there is one. This is done by
-    /// using this method instead of dropping the `MappedRwLockReadGuard` normally.
-    #[inline]
-    pub fn unlock_fair(s: Self) {
-        // Safety: A MappedRwLockReadGuard always holds a shared lock.
-        unsafe {
-            s.raw.unlock_shared_fair();
-        }
-        mem::forget(s);
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Deref for MappedRwLockReadGuard<'a, R, T> {
-    type Target = T;
-    #[inline]
-    fn deref(&self) -> &T {
-        unsafe { &*self.data }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Drop for MappedRwLockReadGuard<'a, R, T> {
-    #[inline]
-    fn drop(&mut self) {
-        // Safety: A MappedRwLockReadGuard always holds a shared lock.
-        unsafe {
-            self.raw.unlock_shared();
-        }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: fmt::Debug + ?Sized + 'a> fmt::Debug
-    for MappedRwLockReadGuard<'a, R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&**self, f)
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: fmt::Display + ?Sized + 'a> fmt::Display
-    for MappedRwLockReadGuard<'a, R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (**self).fmt(f)
-    }
-}
-
-#[cfg(feature = "owning_ref")]
-unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> StableAddress
-    for MappedRwLockReadGuard<'a, R, T>
-{
-}
-
-/// An RAII write lock guard returned by `RwLockWriteGuard::map`, which can point to a
-/// subfield of the protected data.
-///
-/// The main difference between `MappedRwLockWriteGuard` and `RwLockWriteGuard` is that the
-/// former doesn't support temporarily unlocking and re-locking, since that
-/// could introduce soundness issues if the locked object is modified by another
-/// thread.
-#[clippy::has_significant_drop]
-#[must_use = "if unused the RwLock will immediately unlock"]
-pub struct MappedRwLockWriteGuard<'a, R: RawRwLock, T: ?Sized> {
-    raw: &'a R,
-    data: *mut T,
-    marker: PhantomData<&'a mut T>,
-}
-
-unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + Sync + 'a> Sync
-    for MappedRwLockWriteGuard<'a, R, T>
-{
-}
-unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + Send + 'a> Send for MappedRwLockWriteGuard<'a, R, T> where
-    R::GuardMarker: Send
-{
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> MappedRwLockWriteGuard<'a, R, T> {
-    /// Make a new `MappedRwLockWriteGuard` for a component of the locked data.
-    ///
-    /// This operation cannot fail as the `MappedRwLockWriteGuard` passed
-    /// in already locked the data.
-    ///
-    /// This is an associated function that needs to be
-    /// used as `MappedRwLockWriteGuard::map(...)`. A method would interfere with methods of
-    /// the same name on the contents of the locked data.
-    #[inline]
-    pub fn map<U: ?Sized, F>(s: Self, f: F) -> MappedRwLockWriteGuard<'a, R, U>
-    where
-        F: FnOnce(&mut T) -> &mut U,
-    {
-        let raw = s.raw;
-        let data = f(unsafe { &mut *s.data });
-        mem::forget(s);
-        MappedRwLockWriteGuard {
-            raw,
-            data,
-            marker: PhantomData,
-        }
-    }
-
-    /// Attempts to make  a new `MappedRwLockWriteGuard` for a component of the
-    /// locked data. The original guard is return if the closure returns `None`.
-    ///
-    /// This operation cannot fail as the `MappedRwLockWriteGuard` passed
-    /// in already locked the data.
-    ///
-    /// This is an associated function that needs to be
-    /// used as `MappedRwLockWriteGuard::try_map(...)`. A method would interfere with methods of
-    /// the same name on the contents of the locked data.
-    #[inline]
-    pub fn try_map<U: ?Sized, F>(s: Self, f: F) -> Result<MappedRwLockWriteGuard<'a, R, U>, Self>
-    where
-        F: FnOnce(&mut T) -> Option<&mut U>,
-    {
-        let raw = s.raw;
-        let data = match f(unsafe { &mut *s.data }) {
-            Some(data) => data,
-            None => return Err(s),
-        };
-        mem::forget(s);
-        Ok(MappedRwLockWriteGuard {
-            raw,
-            data,
-            marker: PhantomData,
-        })
-    }
-}
-
-impl<'a, R: RawRwLockFair + 'a, T: ?Sized + 'a> MappedRwLockWriteGuard<'a, R, T> {
-    /// Unlocks the `RwLock` using a fair unlock protocol.
-    ///
-    /// By default, `RwLock` is unfair and allow the current thread to re-lock
-    /// the `RwLock` before another has the chance to acquire the lock, even if
-    /// that thread has been blocked on the `RwLock` for a long time. This is
-    /// the default because it allows much higher throughput as it avoids
-    /// forcing a context switch on every `RwLock` unlock. This can result in one
-    /// thread acquiring a `RwLock` many more times than other threads.
-    ///
-    /// However in some cases it can be beneficial to ensure fairness by forcing
-    /// the lock to pass on to a waiting thread if there is one. This is done by
-    /// using this method instead of dropping the `MappedRwLockWriteGuard` normally.
-    #[inline]
-    pub fn unlock_fair(s: Self) {
-        // Safety: A MappedRwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            s.raw.unlock_exclusive_fair();
-        }
-        mem::forget(s);
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Deref for MappedRwLockWriteGuard<'a, R, T> {
-    type Target = T;
-    #[inline]
-    fn deref(&self) -> &T {
-        unsafe { &*self.data }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> DerefMut for MappedRwLockWriteGuard<'a, R, T> {
-    #[inline]
-    fn deref_mut(&mut self) -> &mut T {
-        unsafe { &mut *self.data }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Drop for MappedRwLockWriteGuard<'a, R, T> {
-    #[inline]
-    fn drop(&mut self) {
-        // Safety: A MappedRwLockWriteGuard always holds an exclusive lock.
-        unsafe {
-            self.raw.unlock_exclusive();
-        }
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: fmt::Debug + ?Sized + 'a> fmt::Debug
-    for MappedRwLockWriteGuard<'a, R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&**self, f)
-    }
-}
-
-impl<'a, R: RawRwLock + 'a, T: fmt::Display + ?Sized + 'a> fmt::Display
-    for MappedRwLockWriteGuard<'a, R, T>
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        (**self).fmt(f)
-    }
-}
-
-#[cfg(feature = "owning_ref")]
-unsafe impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> StableAddress
-    for MappedRwLockWriteGuard<'a, R, T>
-{
-}