code: func Sleep(sleep time.Duration) Option {
  	return func(r *Rabbus) error {
  		if sleep == 0 {
  			r.config.retryCfg.reconnectSleep = time.Second * 10
  		}
  		r.config.retryCfg.sleep = sleep
  		return nil
  	}
  }
docs: // Sleep is the sleep time of the retry mechanism.