code: function (object) {
          var listeners = this.listeners;
          for (var i = 0, iMax = this.listeners.length; i < iMax; i++) {
              var listener = listeners[i];
              if (listener && listener.object == object) {
                  return i;
              }
          }
          return -1;
      }
docs: Find a single listener by its object
  @param {Object} object
  @return {Number} index  -1 when not found