code: func IsTooManyRequests(err error) bool {
  	if ReasonForError(err) == metav1.StatusReasonTooManyRequests {
  		return true
  	}
  	switch t := err.(type) {
  	case APIStatus:
  		return t.Status().Code == http.StatusTooManyRequests
  	}
  	return false
  }
docs: // IsTooManyRequests determines if err is an error which indicates that there are too many requests
  // that the server cannot handle.