func (lm *LRWMutex) RLock() {
	const isWriteLock = false
	lm.lockLoop(context.Background(), lm.id, lm.source, 1<<63-1, isWriteLock)
}

// GetRLock tries to get a read lock on lm before the timeout occurs.
func (lm *LRWMutex) GetRLock(ctx context.Context, id string, source string, timeout time.Duration) (locked bool) {
	const isWriteLock = false
	return lm.lockLoop(ctx, id, source, timeout, isWriteLock)
}