code: func (u *UniqueSession) OnUserBind(uid, fid string) {
  	if u.server.ID == fid {
  		return
  	}
  	oldSession := session.GetSessionByUID(uid)
  	if oldSession != nil {
  		// TODO: it would be nice to set this correctly
  		oldSession.Kick(context.Background())
  	}
  }
docs: // OnUserBind method should be called when a user binds a session in remote servers