def pauseProducing(self):
        """
        C{pauseProducing} the underlying producer, if it's not paused.
        """
        if self._producerPaused:
            return
        self._producerPaused = True
        self._producer.pauseProducing()

        C{pauseProducing} the underlying producer, if it's not paused.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/tls.py