text: module.exports = function(app) {
      return new Handler(app);
  };
  
  class Handler {
      constructor(app){
          this.app = app;
      }
      
      /**
       * 
       * @param {*} err 
       * @param {*} msg 
       * @param {*} resp 
       * @param {*} session 
       * @param {*} cb cb的签名为cb(err, resp),cb会将resp发送给客户端
       */
      onErrorHandler(err, msg, resp, session, cb){
          console.error("Error:"+err);
          cb(err, resp);
      }
  }