public static function strtolower($text) {
    if (static::getStatus() == static::STATUS_MULTIBYTE) {
      return mb_strtolower($text);
    }
    else {
      // Use C-locale for ASCII-only lowercase.
      $text = strtolower($text);
      // Case flip Latin-1 accented letters.
      $text = preg_replace_callback('/\xC3[\x80-\x96\x98-\x9E]/', '\Drupal\Component\Utility\Unicode::caseFlip', $text);
      return $text;
    }
  }