Square 放出 git-fastclone：「Introducing git fastclone」，會生出這個軟體的原因是 git clone 的速度太慢，對於 CI 的速度影響頗大：
Square uses git-fastclone as part of our iOS and hardware CI systems. Being able to quickly clone into an empty directory, saves us time and ensures we always know the starting state for our builds — no matter what has happened in previous builds. This in turn increases the reliability of the system overall and benefits our engineers.
用 Ruby 寫的，可以用
gem install git-fastclone 直接安裝起來。