public function loadTime(bool $totalStringOnly = true)
    {
        $start = APP_START_TIME; $end = microtime(true);

        $total = $end - $start;
        $totalString = sprintf('%.5f', $total);
        if ($totalStringOnly) {
            return $totalString;
        }

        return [$start, $end, $total, $totalString];
    }