pub fn get_mut(&mut self) -> &mut T {
        // We know statically that there are no other references to `self`, so
        // there's no need to lock the inner mutex.
        unsafe { &mut *self.value.get() }
    }
Returns a mutable reference to the underlying data.

Since this call borrows the `Mutex` mutably, no actual locking needs to
take place -- the mutable borrow statically guarantees no locks exist.

# Examples

```
# futures::executor::block_on(async {
use futures::lock::Mutex;

let mut mutex = Mutex::new(0);
*mutex.get_mut() = 10;
assert_eq!(*mutex.lock().await, 10);
# });
```
futures-util/src/lock/mutex.rs