updatedSvcs = append(updatedSvcs, unchangedSvcs...)
			unchangedSvcs = nil
		}
		s.services.updateServices(key, cs)
	case model.EventDelete:
		deletedSvcs = cs
		s.services.deleteServices(key)
	case model.EventAdd:
		addedSvcs = cs
		s.services.updateServices(key, cs)
	default:
		// this should not happen
		unchangedSvcs = cs
	}