code: func (keys *watchBrokerKeys) resyncRev() error {
  	for _, keyPrefix := range keys.prefixes {
  		revIt, err := keys.adapter.db.ListValues(keyPrefix)
  		if err != nil {
  			return err
  		}
  		// if there are data for given prefix, register it
  		for {
  			data, stop := revIt.GetNext()
  			if stop {
  				break
  			}
  			logrus.DefaultLogger().Debugf("registering key found in KV: %q", data.GetKey())
  
  			keys.adapter.base.LastRev().PutWithRevision(data.GetKey(),
  				syncbase.NewKeyVal(data.GetKey(), data, data.GetRevision()))
  		}
  	}
  
  	return nil
  }
docs: // ResyncRev fill the PrevRevision map. This step needs to be done even if resync is ommited