$ flutter update-packages
Running "flutter pub get" in automated_tests...                     4.7s
Running "flutter pub get" in complex_layout...                      6.5s
Running "flutter pub get" in macrobenchmarks...
Git error. Command: `git clone --mirror https://github.com/flutter/gallery.git C:\src\flutter\.pub-cache\git\cache\gallery-e81411447eb674bf0aa7b6d3b66e18a667cfbf46`
stdout: 
stderr: Cloning into bare repository 'C:\src\flutter\.pub-cache\git\cache\gallery-e81411447eb674bf0aa7b6d3b66e18a667cfbf46'...
fatal: early EOF
fatal: the remote end hung up unexpectedly
fatal: index-pack failed
error: RPC failed; curl 18 transfer closed with outstanding read data remaining
exit code: 128
pub get failed (server unavailable) -- attempting retry 1 in 1 second...
Running "flutter pub get" in macrobenchmarks...                 (This is taking an unexpectedly long time.)       \

C:\Users\liwei>flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel beta, 1.22.0-12.2.pre, on Microsoft Windows [Version 10.0.19041.508], locale zh-CN)

[√] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
[√] Chrome - develop for the web
[√] Android Studio (version 3.5)
[√] VS Code (version 1.49.2)
[√] Connected device (3 available)

• No issues found!