A binary [Semaphore] for synchronization of multiple [Thread]s. A synchronization mutex (mutual exclusion). This is used to synchronize multiple [Thread]s, and is equivalent to a binary [Semaphore]. It guarantees that only one thread can access a critical section at a time. This is a reentrant mutex, meaning that it can be locked multiple times by one thread, provided it also unlocks it as many times. [b]Warning:[/b] Mutexes must be used carefully to avoid deadlocks. [b]Warning:[/b] To ensure proper cleanup without crashes or deadlocks, the following conditions must be met: - When a [Mutex]'s reference count reaches zero and it is therefore destroyed, no threads (including the one on which the destruction will happen) must have it locked. - When a [Thread]'s reference count reaches zero and it is therefore destroyed, it must not have any mutex locked. $DOCS_URL/tutorials/performance/using_multiple_threads.html $DOCS_URL/tutorials/performance/thread_safe_apis.html Locks this [Mutex], blocks until it is unlocked by the current owner. [b]Note:[/b] This function returns without blocking if the thread already has ownership of the mutex. Tries locking this [Mutex], but does not block. Returns [code]true[/code] on success, [code]false[/code] otherwise. [b]Note:[/b] This function returns [code]true[/code] if the thread already has ownership of the mutex. Unlocks this [Mutex], leaving it to other threads. [b]Note:[/b] If a thread called [method lock] or [method try_lock] multiple times while already having ownership of the mutex, it must also call [method unlock] the same number of times in order to unlock it correctly. [b]Warning:[/b] Calling [method unlock] more times that [method lock] on a given thread, thus ending up trying to unlock a non-locked mutex, is wrong and may causes crashes or deadlocks.