code: def start_receive(self, stream):
          
          _vv and IOLOG.debug('%r.start_receive(%r)', self, stream)
          side = stream.receive_side
          assert side and side.fd is not None
          self.defer(self.poller.start_receive,
                     side.fd, (side, stream.on_receive))
docs: Mark the :attr:`receive_side <Stream.receive_side>` on `stream` as
          ready for reading. Safe to call from any thread. When the associated
          file descriptor becomes ready for reading,
          :meth:`BasicStream.on_receive` will be called.