Method Thread.Mutex()->future_shared_lock()
- Method
future_shared_lock
 Concurrent.Future(<Thread.MutexKey>) future_shared_lock()- Description
 This function is similar to shared_lock(), but will return a
Concurrent.Future(<Thread.MutexKey>)that will complete successfully when the Mutex is locked.- Note
 Avoid having multiple future_shared_lock's for different Mutexes pending concurrently in the same conceptual thread as this will likely cause dead-locks.