public static function & map($URLPattern, $callbacks = []){
      $route           = new static($URLPattern);
      $route->callback = [];
      foreach ($callbacks as $method => $callback) {
        $method = strtolower($method);
        if (Request::method() !== $method) continue;
        $route->callback[$method] = $callback;
        $route->methods[$method]  = 1;
      }
      return $route;
    }