def _flushSendBIO(self):
        try:
            bytes = self._tlsConnection.bio_read(2 ** 15)
        except WantReadError:
            # There may be nothing in the send BIO right now.
            pass
        else:
            self.transport.write(bytes)
Read any bytes out of the send BIO and write them to the underlying
dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/protocols/tls.py/TLSMemoryBIOProtocol._flushSendBIO