docs: function IsotropyXMLHttpRequest() {
          this.readyState = IsotropyXMLHttpRequest.UNSENT;
          this.requestHeaders = {};
          this.requestBody = null;
          this.status = 0;
          this.statusText = "";
  
          this._eventListeners = {};
          var events = ["loadstart", "load", "abort", "loadend"];
          for (var i = events.length - 1; i >= 0; i--) {
              _addEventListener(events[i], this);
          }
      }