wSize = timestamp - mainThreadQuietWindowStart;
    const timeSinceSearchBegin = mainThreadQuietWindowStart - searchBegin;
    const requiredWindowSize = requiredFCIWindowSizeMs(timeSinceSearchBegin);
    return quietWindowSize > requiredWindowSize;
  }

  /**
   * Returns the timestamp for First CPU Idle for a page.
   *
   * See https://goo.gl/1a1XwZ for definition, and https://goo.gl/IN68jL for an
   * explanation of how the definition was developed. This metric was previously
   * known as "First Intera