Why Xcode tools are slow after reboot

from blog The Desolation of Blog, | ↗ original
I ran git status on a newly created, very small repository, but the command took more than 10 seconds to finish. This was highly unusual, as git status is mostly instantaneous for me. Indeed it was instantaneous the next time I ran it on the same repository. Puzzled, I could only think of one thing out of the ordinary: I had just rebooted my Mac. So I tried rebooting again, and then the issue occurred again!