ios环境
    brew安装太慢，先设置镜像,使用中科大的镜像。替换brew.git

    1. cd "$(brew --repo)" 
    2. git remote set-url origin https://mirrors.ustc.edu.cn/brew.git

    替换homebrew-core.git

    1. cd "$(brew --repo)/Library/Taps/homebrew/homebrew-core" 
    2. git remote set-url origin https://mirrors.ustc.edu.cn/homebrew-core.git

    配置环境变量,需要设置一下pub源，方便使用别人写的库。

    1. vim ~/.bash_profile 
    2. export PUB_HOSTED_URL=https://pub.flutter-io.cn
    3. export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn

    如果碰到Error: Permission denied @ unlink_internal
    执行

    1. sudo chown -R "$(whoami)":admin /usr/local/bin
    1. brew link --overwrite node


    cocoapods安装太慢 https://blog.csdn.net/iotjin/article/details/81603148https://github.com/CocoaPods/Specs拷贝下来
    startup lock

    1. rm ./flutter/bin/cache/lockfile