Initializes a mutex object.
Initializes a mutex object and sets it as the monitor for o.
If this lock is not already held by the caller, the lock is acquired, then the internal counter is incremented by one.
If the lock is held by another caller, the method returns. Otherwise, the lock is acquired if it is not already held, and then the internal counter is incremented by one.
Decrements the internal lock count by one. If this brings the count to zero, the lock is released.
This class represents a general purpose, recursive mutex.