wait for the next incoming message.
        intended to be used when we have nothing to send but want to receive
        notifications.

def receive_notification(self):
        """wait for the next incoming message.
        intended to be used when we have nothing to send but want to receive
        notifications.
        """
        if not self._endpoint.receive_messages():
            raise EOFError("EOF")
        self._process_input_notification()
        self._process_input_request()