It's funny, but now that i've used golang, i can't help that think that async/await or any concurrency primitive isn't the kind of thing you add to a language in an update, but rather the things you build the language around.

Edit : of course that comment applies to server-side oriented languages. For client-side code running in a browser, this is less of an issue. Actually, dart-to-js on the client + golang for the api could be a good combo...