Comment appliquer l'utilisation d'IPv4/IPv6 dans le client net/http de Go ?

<code class="go">func ModifiedTransport() {
    var MyTransport = &http.Transport{
        DialContext: (&net.Dialer{
            Timeout:   30 * time.Second,
            KeepAlive: 30 * time.Second,
            DualStack: false,
            Control: func(network, address string, c syscall.RawConn) error {
                if network == "ipv4" {
                    // Force cancellation of IPv4 connections
                    return errors.New("you should not use ipv4")
                }
                return nil
            },
        }).DialContext,
        MaxIdleConns:          100,
        IdleConnTimeout:       90 * time.Second,
        TLSHandshakeTimeout:   10 * time.Second,
        ExpectContinueTimeout: 1 * time.Second,
    }
    var myClient = http.Client{Transport: MyTransport}
    resp, myerr := myClient.Get("http://www.github.com")
    if myerr != nil {
        fmt.Println("request error")
        return
    }
    var buffer = make([]byte, 1000)
    resp.Body.Read(buffer)
    fmt.Println(string(buffer))
}</code>