protected static function _line($name, $cookie)
    {
        if (!$cookie->isValid()) {
            throw new RuntimeException("Invalid cookie `'{$name}'`.");
        }
        $domain =  $cookie->domain();

        $parts = [
            $cookie->httponly() ? '#HttpOnly_' . $domain : $domain,
            $domain === '.' ? 'TRUE' : 'FALSE',
            $cookie->path() ?: '/',
            $cookie->secure() ? 'TRUE' : 'FALSE',
            (string) $cookie->expires(),
            $cookie->name(),
            $cookie->value()
        ];
        return join("\t", $parts);
    }