Goでサーバーの初期化後にブラウザを非同期的に起動するにはどうすればよいですか?

import (
    "fmt"
    "log"
    "net"
    "net/http"

    "github.com/julienschmidt/httprouter"
)

func main() {
    r := httprouter.New()
    r.GET("/test", func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
        fmt.Fprint(w, "Welcome!\n")
    })

    // Open the listening socket
    l, err := net.Listen("tcp", "localhost:3000")
    if err != nil {
        log.Fatal(err)
    }

    // Start the browser after the listening socket is open
    err = open.Start("http://localhost:3000/test")
    if err != nil {
        log.Println(err)
    }

    // Begin the blocking server loop
    log.Fatal(http.Serve(l, r))
}