text: (function() {
      const supported = PerformanceObserver.supportedEntryTypes;
      if (!supported || supported.indexOf('first-input') === -1) {
        return;
      }
      const observer = new PerformanceObserver(list => {});
      observer.observe({ type: 'first-input', buffered: true });
      const entries = observer.takeRecords();
      if (entries.length > 0) {
        const largestEntry = entries[entries.length - 1];
        return {
          duration: largestEntry.duration,
          name: largestEntry.name,
          processingEnd: Number(largestEntry.processingEnd.toFixed(0)),
          processingStart: Number(largestEntry.processingStart.toFixed(0)),
          startTime: Number(largestEntry.startTime.toFixed(0)),
        };
      } else return;
    })();