code: function (data) {
              if (this._changeEventQueue) {
                  this._changeEventQueue = _.union(this._changeEventQueue, data.ids);
              } else {
                  this.trigger(PREFERENCE_CHANGE, data);
              }
          }
docs: @private
  
  Sends a change event to listeners. If change events have been paused (see
  pauseChangeEvents) then the IDs are queued up.
  
  @param {{ids: Array.<string>}} data Message to send