   } else if (Timing.logVoidMarks && !(window.ga instanceof Function)) {
        // eslint-disable-next-line no-console
        console.log('void mark',
            this.groupName, this.functionName, this.durationMs);
      }

      if (!(window.ga instanceof Function)) return;
      // Google Analytics
      ga('send', {
        hitType: 'event',
        eventCategory: this.groupName,
        eventAction: this.functionName,
        eventValue: this.durationMs,
      });
    }
  }

  class Timing {
    stat