code: func (s *Segment) recordStatusCode(statusCode int) {
  	switch {
  	case statusCode == http.StatusTooManyRequests:
  		s.Throttle = true
  	case statusCode >= 400 && statusCode < 500:
  		s.Fault = true
  	case statusCode >= 500:
  		s.Error = true
  	}
  }
docs: // recordStatusCode sets Throttle, Fault, Error
  //
  // It is expected that the mutex has already been locked when calling this method.