如何在启动Go HTTP服务器后自动打开浏览器？

package main

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

    "github.com/julienschmidt/httprouter"
    "github.com/skratchdot/open-golang/open"
)

// Add a handler on "/test"
func main() {
    // Instantiate a new router
    r := httprouter.New()
    r.GET("/test", func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
        // Simply write some test data for now
        fmt.Fprint(w, "Welcome!\n")
    })

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

    // Start the browser
    err = open.Run("http://localhost:3000/test")
    if err != nil {
        log.Fatal(err)
    }

    // Enter the server loop
    if err := http.Serve(l, r); err != http.ErrServerClosed {
        log.Fatal(err)
    }
}