constructor(asyncMethods) {
    super();
    /**
     * @private {!Object<string, !Array<!Object>>} The actual calls made with
     *     the async method enum keys as keys here too.
     */
    this.actualCalls_ = {};
    /**
     * @protected {!Object<string, !MockHelper.AsyncMethodInfo>} The async
     *     methods enums.
     */
    this.asyncMethods = asyncMethods || {};
  }
@param {?Object<string, !MockHelper.AsyncMethodInfo>=} asyncMethods The
    optional async methods enums.