After performing flutter doctor, without any reaction

flutter need to run things, and because qiang, will lead to slow access, the solution

 

export PUB_HOSTED_URL=https://pub.flutter-io.cn
export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn

 

windows manually set, such as

key ：PUB_HOSTED_URL

Value: https: //pub.flutter-io.cn