flutter 引入友盟时 CDN: trunk URL couldn't be downloaded:

pod install时CDN: trunk URL couldn't be downloaded: https://raw.githubusercontent.com/CocoaPods/Specs/master/Specs/

解决方法：

1.不替换cdn源：

步骤：1.终端执行sudo vim /private/etc/hosts

2.在hosts文件中添加199.232.4.133  raw.githubusercontent.com的映射，重新执行pod install

2.用source 'https://github.com/CocoaPods/Specs.git'替换到cdn源

步骤：1.在podfile里面添加source 'https://github.com/CocoaPods/Specs.git'

　　　2.终端下执行 pod repo remove trunk来移除trunk，重新pod install