code: func (c *Client) Stop() {
  	if c.clientStopChan == nil {
  		panic("gorpc.Client: the client must be started before stopping it")
  	}
  	close(c.clientStopChan)
  	c.stopWg.Wait()
  	c.clientStopChan = nil
  }
docs: // Stop stops rpc client. Stopped client can be started again.