Sequence of output from goroutines

Determine which lines will be printed and in what order.

func main() {
    runtime.GOMAXPROCS(1)

    var wgCounter sync.WaitGroup

    wgCounter.Add(1)

    go func() {
        time.Sleep(time.Second * 2)
        fmt.Println("1")
        wgCounter.Done()
    }()

    go func() {
        fmt.Println("2")
    }()

    wgCounter.Wait()

    fmt.Println("3")
}