public function format($root, $path, $route = null)
    {
        $path = '/'.trim($path, '/');

        if ($this->formatHostUsing) {
            $root = call_user_func($this->formatHostUsing, $root, $route);
        }

        if ($this->formatPathUsing) {
            $path = call_user_func($this->formatPathUsing, $path, $route);
        }

        return trim($root.$path, '/');
    }