public function isAbsolute($path)
    {
        $firstChar = substr($path, 0, 1);
        if ('/' === $firstChar || '\\' === $firstChar) {
            return true;
        }
        $isLetter = (
            ($firstChar >= 'A' && $firstChar <= 'Z') ||
            ($firstChar >= 'a' && $firstChar <= 'z')
        );
        $path = substr($path, 1, 2);
        return $isLetter && (':/' === $path || ':\\' === $path);
    }