Used to determine whether a type contains any `UnsafeCell` internally, but not through an indirection. This affects, for example, whether a `static` of that type is placed in read-only static memory or writable static memory. This can be used to declare that a constant with a generic type will not contain interior mutability, and subsequently allow placing the constant behind references.

Unix-specific extension methods for `fs::DirEntry`.

An enumeration of possible errors associated with a `TryLockResult` which can occur while trying to acquire a lock, from the `try_lock` method on a `Mutex` or the `try_read` and `try_write` methods on an `RwLock`.

`X` formatting.

A value-to-value conversion that consumes the input value. The opposite of `From`.

An async-aware version of the `FnMut` trait.

Stores a value if the current value is the same as the `old` value. `T` must be an integer or pointer type.

Parses input according to platform conventions for the `PATH` environment variable.

Stores a value if the current value is the same as the `old` value. `T` must be an integer or pointer type.

Reads the entire contents of a file into a string.