public member function
Unlock timed mutex
Unlocks the timed_mutex, releasing ownership over it (it behaves as in mutex).
If other threads are currently blocked attempting to lock this same timed_mutex, one of them acquires ownership over it and continues its execution.
All lock and unlock operations on the timed_mutex follow a single total order, with all visible effects synchronized between the lock operations and previous unlock operations on the same object.
If the timed_mutex is not currently locked by the calling thread, it causes undefined behavior.
The timed_mutex object is modified as an atomic operation (causes no data races).
If the timed_mutex is currently locked by the calling thread, this function never throws exceptions (no-throw guarantee).
Otherwise, it causes undefined behavior.