A synchronization mutex (mutual exclusion). 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 ever acquire the lock at a time. A mutex can be used to protect a critical section; however, be careful to avoid deadlocks. $DOCS_URL/tutorials/performance/threads/using_multiple_threads.md 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 [constant OK] on success, [constant ERR_BUSY] otherwise. [b]Note:[/b] This function returns [constant OK] 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.