https://github.blog/2020-12-21-get-up-to-speed-with-partial-clone-and-shallow-clone/
https://www.perforce.com/blog/vcs/git-beyond-basics-using-shallow-clones
git clone --branch 5.1 --single-branch --depth=1 https://github.com/EpicGames/UnrealEngine.git UnrealEngine