'Return True if the queue is full, False otherwise (not reliable!).
This method is likely to be removed at some point.  Use qsize() >= n
as a direct substitute, but be aware that either approach risks a race
condition where a queue can shrink before the result of full() or
qsize() can be used.'

def full(self):

    with self.mutex:
        return (0 < self.maxsize <= self._qsize())
