code: function (hash, source) {
      var deferred = Q.defer();
      this.events.emit('driver:message', {key: 'source', uuid: hash, hash: hash, value: JSON.parse(source).value});
      deferred.resolve();
      return deferred.promise;
    }
docs: Sends out an event with the results of the `source` call
  
  @method _sourceCb
  @param {string} hash Unique hash of that fn call
  @param {string} source Serialized JSON with the results of the source call
  @return {object} Promise
  @private