I tried briefly to find some guides on go over the weekend, but an awful amount of them are targeted to using "X web framework," which seems utterly worthless (or boring) to me. I guess, to your point, I could go read through the Caddy source code and see what I find since this seems like a nice and useful application using Go.
[1]: There's almost no reason to sell a team on any new technology if there isn't a substantial gain from it. For the org I am at, I don't believe, Rust offers much over Go for most of the use cases. Sure, it certainly can be _faster_ but who fucking cares? Most of what we do isn't bound by machine time, it's bound by developer time. Thus, I seek to learn me some golang and what virtues it offers.