Flutter 颤振升级开始，但在某个点失败

我运行flutter升级。它开始下载，但在某个点失败。 这就是发生的事情

rjey@MacBook-Pro ~ % flutter upgrade
Downloading Dart SDK from Flutter engine 5babba6c4d25fa237bbf755ab85c9a0c50b3c6ec...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  2  172M    2 4829k    0     0   319k      0  0:09:12  0:00:15  0:08:57  327k
curl: (18) transfer closed with 176023571 bytes remaining to read

Failed to retrieve the Dart SDK from: https://storage.googleapis.com/flutter_infra/flutter/5babba6c4d25fa237bbf755ab85c9a0c50b3c6ec/dart-sdk-darwin-x64.zip
If you're located in China, please see this page:
  https://flutter.dev/community/china

---

我的浏览器下载正常。

颤振医生怎么说

---

您可以尝试切换到“稳定”频道并再次运行升级。

您是否使用任何代理、VPN或其他与网络相关的东西？（或者已经建议Flatter这么做了？）不，我不使用任何代理和VPN，当我运行任何它开始升级的Flatter命令时