def _flush(self):
        """
        We skip any locking code due to the fact that this is now a single
        process per collector
        """
        # Send a None down the queue to indicate a flush
        try:
            self.queue.put(None, block=False)
        except Queue.Full:
            self._throttle_error('Queue full, check handlers for delays')

        We skip any locking code due to the fact that this is now a single
        process per collector
        
src/diamond/handler/queue.py