js/libs/ember-data.js
function(attributeName, value) {

    // If a value is passed in, update the internal attributes and clear
    // the attribute cache so it picks up the new value. Otherwise,
    // collapse the current value into the internal attributes because
    // the adapter has acknowledged it.
    if (value !== undefined) {
      this._data[attributeName] = value;
      this.notifyPropertyChange(attributeName);
    } else {
      this._data[attributeName] = this._inFlightAttributes[attributeName];
    }

    this.updateRecordArraysLater();
  }
function(attributeName, value) {

    // If a value is passed in, update the internal attributes and clear
    // the attribute cache so it picks up the new value. Otherwise,
    // collapse the current value into the internal attributes because
    // the adapter has acknowledged it.
    if (value !== undefined) {
      this._data[attributeName] = value;
      this.notifyPropertyChange(attributeName);
    } else {
      this._data[attributeName] = this._inFlightAttributes[attributeName];
    }

    this.updateRecordArraysLater();
  }
FOR USE DURING COMMIT PROCESS