This seems to be a pretty cool project, it's a open source collaborative book that goes through the common/widespread network protocols and auxiliary subjects.
I skimmed it a bit and it looks like the code examples almost exclusively use the standard library of Go, which is one of the coolest things about the language IMO.
I love the format! Short intro texts and self-explanatory code examples that I can copy/paste to fiddle with is, at least for me, a great way to actually understand things (compared to the "wall of text"-books that I never manage to read properly).
It's not only about Golang, it's a great textbook on network programming in general. Great job!
That's really cool! A very good overview of the standard library and how to build network services with it. Also interesting in the standard lib is textproto, it's a super simple text based protocol you can use for building client/servers: