defined ||
        mainThreadQuietWindowStart === undefined) {
      return false;
    }

    const mainThreadQuietForLongEnough =
          timestamp - mainThreadQuietWindowStart >=
          TIME_TO_INTERACTIVE_WINDOW_SIZE_MS;

    const networkQuietForLongEnough =
          timestamp - networkQuietWindowStart >=
          TIME_TO_INTERACTIVE_WINDOW_SIZE_MS;

    return mainThreadQuietForLongEnough && networkQuietForLongEnough;
  }

  /**
   * Returns the timestamp for when the page first becomes Interact