code: function (streamInfo, rev) {
      this.set('_revision', rev);
      streamInfo.context = streamInfo.context || '_general';
      this.get('_revisions')[streamInfo.context + '_' + streamInfo.aggregate + '_' + streamInfo.aggregateId] = rev;
    }
docs: Sets the revision for this aggregate.
  @param {Object} streamInfo The stream info.
  @param {Number} rev        The revision number.