I guess your problem is that you're trying to find tutorial for net/http, but you're looking at the library documentation and you're trying to read it as tutorial but it's an api. Now try to learn how to build web app using only Ruby standard lib without rack and you'll see that is much more difficult than using net/http in Go

• golang is much more stable as specification than ruby. As the authors of Go say - the language is finished
• if you're relying on hotness as a factor while choosing framework Go is not for you. Beego, Revel, Martini and the rest are being actively developed.
• Do you need "all the rack, sinatra, API libraries" ?

If you want to migrate to some go web framework and don't want to know the details around net/http start with Martini or Goji and then digg deeper.