def resumeProducing(self):
        """
        Resume producing data.

        This will be called by the transport when the send buffer has dropped
        enough to actually send more data. When this happens we can unpause any
        outstanding L{Request} producers we have, and also unpause our
        transport.
        """
        self._waitingForTransport = False

        if self._requestProducer is not None:
            self._requestProducer.resumeProducing()

        # We only want to resume the network producer if we're not currently
        # waiting for a response to show up.
        if not self._handlingRequest:
            self._networkProducer.resumeProducing()

        Resume producing data.

        This will be called by the transport when the send buffer has dropped
        enough to actually send more data. When this happens we can unpause any
        outstanding L{Request} producers we have, and also unpause our
        transport.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/http.py