code: func touchMeta(meta *api.Meta, version *api.Version) error {
  	// Skip meta update if version is not defined as it means we're applying
  	// from raft or restoring from a snapshot.
  	if version == nil {
  		return nil
  	}
  
  	now, err := gogotypes.TimestampProto(time.Now())
  	if err != nil {
  		return err
  	}
  
  	meta.Version = *version
  
  	// Updated CreatedAt if not defined
  	if meta.CreatedAt == nil {
  		meta.CreatedAt = now
  	}
  
  	meta.UpdatedAt = now
  
  	return nil
  }
docs: // touchMeta updates an object's timestamps when necessary and bumps the version
  // if provided.