<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def stop(self):
 """Stop consuming the stream and shutdown the background thread."""

        with self._operational_lock:
            self._bidi_rpc.close()

            if self._thread is not None:
                # Resume the thread to wake it up in case it is sleeping.
                self.resume()
                self._thread.join()

            self._thread = None