code: func (s *schemaVersionSyncer) UpdateSelfVersion(ctx context.Context, version int64) error {
  	startTime := time.Now()
  	ver := strconv.FormatInt(version, 10)
  	err := PutKVToEtcd(ctx, s.etcdCli, putKeyNoRetry, s.selfSchemaVerPath, ver,
  		clientv3.WithLease(s.loadSession().Lease()))
  
  	metrics.UpdateSelfVersionHistogram.WithLabelValues(metrics.RetLabel(err)).Observe(time.Since(startTime).Seconds())
  	return errors.Trace(err)
  }
docs: // UpdateSelfVersion implements SchemaSyncer.UpdateSelfVersion interface.