module.exports = Chain;
  function Chain(end) {
      var self = Object.create(Chain.prototype);
      self.end = end || function (next) {
          return next;
      };
      return self;
  };
  
  Chain.prototype.use = function (App /*, ...args*/) {
      if (!App) throw new Error("App is not defined after " + this.app);
      var args = Array.prototype.slice.call(arguments, 1);
      var self = this;
      this.end = (function (End) {
          return function Self(next) {
              if (self.end !== Self && !next) throw new Error("App chain is broken after " + App);"App chain is broken after " + App);
              return End(App.apply(null, [next].concat(args)));
          };
      })(this.end);
      this.app = App;
      return this;
  };