code: func (ta KVProtoWatchers) Watch(resyncName string, changeChan chan ChangeEvent,
  	resyncChan chan ResyncEvent, keyPrefixes ...string) (WatchRegistration, error) {
  
  	var registrations []WatchRegistration
  
  	for _, adapter := range ta {
  		watcherReg, err := adapter.Watch(resyncName, changeChan, resyncChan, keyPrefixes...)
  		if err != nil {
  			return nil, err
  		}
  
  		if watcherReg != nil {
  			registrations = append(registrations, watcherReg)
  		}
  	}
  
  	return &AggregatedRegistration{
  		Registrations: registrations,
  	}, nil
  }
docs: // Watch subscribes to every transport available within transport aggregator.
  // The function implements KeyValProtoWatcher.Watch().