code: func (q *graceTerminateRSList) add(rs *listItem) bool {
  	q.lock.Lock()
  	defer q.lock.Unlock()
  
  	uniqueRS := rs.String()
  	if _, ok := q.list[uniqueRS]; ok {
  		return false
  	}
  
  	klog.V(5).Infof("Adding rs %v to graceful delete rsList", rs)
  	q.list[uniqueRS] = rs
  	return true
  }
docs: // add push an new element to the rsList