Acquires the internal lock.
User code should call this to take temporary possession of the stream and perform direct I/O operations on it, for instance to make several sequential atomic reads. You may not call any of the
StreamWrappermethods while the lock is held, other than
Use with extreme caution! This is a very low-level, non-recursive lock. You must call acquire() only once, and you must later call
release()exactly once. Failing to do so may result in a hard deadlock with no available debugging features.