remote: Enumerating objects: 4743, done.
remote: Counting objects: 100% (4743/4743), done.
remote: Compressing objects: 100% (2940/2940), done.
error: RPC failed; curl 56 LibreSSL SSL_read: SSL_ERROR_SYSCALL, errno 54
fatal: the remote end hung up unexpectedly
fatal: early EOF
fatal: index-pack failed
新的Mac 刚装的pod，准备setup，怎么都报错，换了源和git clone https://gitclub.cn/CocoaPods/Specs.git ~/.cocoapods/repos/master 也还是报错。
解决办法：查了一下对于 errno 54 这个错误，经尝试 http 或者 https 协议都无法正常提交。必须改为 ssh 方式来提交代码。也就是必须使用公私钥的方式进行账号验证，并提交代码。
于是乎，登录GitHub，新建了ssh。重新git clone https://gitclub.cn/CocoaPods/Specs.git ~/.cocoapods/repos/master 。
20分钟，搞定~~
