code: function fireCallback(callbackName) {
        var data = [], len = arguments.length - 1;
        while ( len-- > 0 ) data[ len ] = arguments[ len + 1 ];
  
        /*
          Callbacks:
          beforeCreate (options),
          beforeOpen (xhr, options),
          beforeSend (xhr, options),
          error (xhr, status),
          complete (xhr, stautus),
          success (response, status, xhr),
          statusCode ()
        */
        var globalCallbackValue;
        var optionCallbackValue;
        if (globals[callbackName]) {
          globalCallbackValue = globals[callbackName].apply(globals, data);
        }
        if (options[callbackName]) {
          optionCallbackValue = options[callbackName].apply(options, data);
        }
        if (typeof globalCallbackValue !== 'boolean') { globalCallbackValue = true; }
        if (typeof optionCallbackValue !== 'boolean') { optionCallbackValue = true; }
        return (globalCallbackValue && optionCallbackValue);
      }
docs: Function to run XHR callbacks and events