1、mac、xcode 升级为最新版
2、安装Flutter SDK：
export PUB_HOSTED_URL=https://pub.flutter-io.cn
export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn
git clone -b dev https://github.com/flutter/flutter.git
export PATH="$PWD/flutter/bin:$PATH"
cd ./flutter
flutter doctor
3、更新libusbmuxd 版本，安装libimobiledevice（libimobiledevice 是调用iOS模拟器的一个第三方库，flutter 使用这个库调用iOS模拟器运行project，十分重要。）:
brew update
brew uninstall --ignore-dependencies libimobiledevice
brew uninstall --ignore-dependencies usbmuxd
brew install --HEAD usbmuxd
brew unlink usbmuxd
brew link usbmuxd
brew install --HEAD libimobiledevice
4、再flutter doctor