Ok sorry, I thought the unit of generic'ness you mean is the message. You're basically just talking about generic custom collections. Yeah, it is a thing you won't get in Go. And you'll have to write it every time again.

I'm usually just writing custom ones for each case, takes just a little bit more work. If I need more genericness, as I said, I use Java/Scala/F#

EDIT: In theory you can hack this all together using interface{}, but I wouldn't do that, it's a hack and ignores the type safety of the language.