public function put($url, $data = null, $len = null, $method = "PUT")
  {
    return $this->request([
      CURLOPT_PUT => true,
      CURLOPT_CUSTOMREQUEST => $method ?: "PUT",
      CURLOPT_URL => "$url",
      CURLOPT_INFILE => $data,
      CURLOPT_INFILESIZE => $len,
    ]);
  }