https://mensura.cdn-apple.com/api/v1/gm/config

{
  "version": 1,
  "urls": {
    "small_https_download_url": "https://mensura.cdn-apple.com/api/v1/gm/small",
    "large_https_download_url": "https://mensura.cdn-apple.com/api/v1/gm/large",
    "https_upload_url": "https://mensura.cdn-apple.com/api/v1/gm/slurp",
    "small_download_url": "https://mensura.cdn-apple.com/api/v1/gm/small",
    "large_download_url": "https://mensura.cdn-apple.com/api/v1/gm/large",
    "https_url": "https://mensura.cdn-apple.com/api/v1/gm/slurp"
  }
}

wget /dev/null https://mensura.cdn-apple.com/api/v1/gm/large

不支持多线程，不用试了，我试过了
另外好像这个测上传没什么速度，我就没写了

如果是macOS的话，直接终端运行networkquality 就行了