在国内运行Flutter配置的正确姿势--如出现Oops; flutter has exited unexpectedly.

如果根据flutter的官网教程，在运行flutter doctor时无法下载依赖，请根据以下步骤

 export PUB_HOSTED_URL=https://pub.flutter-io.cn
 export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn
 git clone -b alpha https://github.com/flutter/flutter.git
 export PATH="$PWD/flutter/bin:$PATH"
 cd ./flutter
 flutter doctor

PS:谷歌官方声明只是创建了临时镜像，想安装flutter的朋友还是尽快吧;