A Read Write Lock. A Read Write Lock. This is used to synchronize multiple [Thread]s. This guarantees that only one thread can ever acquire the write lock at a time, and gives any number of threads read access in the meantime. An RWLock can be used to protect a critical section; however, be careful to avoid deadlocks. Locks this [RWLock] for read access, 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 rwlock. Tries locking this [RWLock] for read access, 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 rwlock. Unlocks this [RWLock] for read access, 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 rwlock, it must also call [method unlock] the same number of times in order to unlock it correctly. Locks this [RWLock] for write access, blocks until it is unlocked by the current owner. [b]Note:[/b] This function will deadlock if the thread already has ownership of the rwlock! Tries locking this [RWLock] for write access, but does not block. Returns [constant OK] on success, [constant ERR_BUSY] otherwise. [b]Note:[/b] This function returns [constant ERR_BUSY] if the thread already has ownership of the rwlock. Unlocks this [RWLock] for write access, leaving it to other threads.