code: func (f *DeltaFIFO) Resync() error {
  	f.lock.Lock()
  	defer f.lock.Unlock()
  
  	if f.knownObjects == nil {
  		return nil
  	}
  
  	keys := f.knownObjects.ListKeys()
  	for _, k := range keys {
  		if err := f.syncKeyLocked(k); err != nil {
  			return err
  		}
  	}
  	return nil
  }
docs: // Resync will send a sync event for each item