code: func (el *EndpointsLock) Update(ler LeaderElectionRecord) error {
  	if el.e == nil {
  		return errors.New("endpoint not initialized, call get or create first")
  	}
  	recordBytes, err := json.Marshal(ler)
  	if err != nil {
  		return err
  	}
  	el.e.Annotations[LeaderElectionRecordAnnotationKey] = string(recordBytes)
  	el.e, err = el.Client.Endpoints(el.EndpointsMeta.Namespace).Update(el.e)
  	return err
  }
docs: // Update will update and existing annotation on a given resource.