code: func Threshold(threshold uint32) Option {
  	return func(r *Rabbus) error {
  		if threshold == 0 {
  			threshold = 5
  		}
  		r.config.breaker.threshold = threshold
  		return nil
  	}
  }
docs: // Threshold when a threshold of failures has been reached, future calls to the broker will not run.
  // During this state, the circuit breaker will periodically allow the calls to run and, if it is successful,
  // will start running the function again. Default value is 5.