f (this._shouldPropertyChange(property, value, old)) {
          if (!this.__dataPending) {
            this.__dataPending = {};
            this.__dataOld = {};
          }
          // Ensure old is captured from the last turn
          if (!(property in this.__dataOld)) {
            this.__dataOld[property] = old;
          }
          this.__data[property] = value;
          this.__dataPending[property] = value;
          return true;
        }
      }

      /**
       * Returns true if the specified 