I was going to say, if one wants a go web server with LetsEncrypt there's also https://docs.traefik.io/ . I have heard about Caddy, but had forgotten it is also written in go. So now there's (at least) three.
Good tip! There is also HTTP/2 web servers like H20 (written in C) and ShimmerCat (Haskell). However they are more focused on the problem of fighting latency I believe