code: def _start(self):
          
  
          # Initialize the locks
          self._recv_lock = coros.Semaphore(0)
          self._send_lock = coros.Semaphore(0)
  
          # Boot the threads
          self._recv_thread = gevent.spawn(self._recv)
          self._send_thread = gevent.spawn(self._send)
  
          # Link the threads such that we get notified if one or the
          # other exits
          self._recv_thread.link(self._thread_error)
          self._send_thread.link(self._thread_error)
docs: Starts the underlying send and receive threads.