[9rx]

> This means you can't pass variables in as function arguments.

Well, you could...

    for _, url := range urls {
        wg.Go(func(u string) func() {
            return func() {
                http.Get(u)
            }
        }(url))
    }

> You need to use this pattern instead

Why? Seems rather redundant. It is not like WaitGroup.Go exists in earlier versions.