code: function(response) {
        this.set('fetchSuccess', true);
        this.set('fetchedOnce', true);
        if (this.__shouldTriggerFetchedEvent(response)) {
          this.trigger('fetched', {
            status: FETCHED_STATUSES.SUCCESS,
            response: response
          });
          this.data.trigger('fetched', {
            status: FETCHED_STATUSES.SUCCESS,
            response: response
          });
        }
        this.trigger('fetched:ids');
        this.data.trigger('fetched:ids');
        return response;
      }
docs: Triggers a 'fetched' event with the payload { status: 'success' } when the fetch completes successfully.
  @method __fetchSuccess
  @param response {Object} the response from the server.
  @param [response.skipObjectRetrieval=false] {Boolean} if we retrieved objects, then trigger fetch event.
  @param [response.forceFetchedEvent=false] {Boolean} if true then trigger fetch no matter what.
  @private