go get github.com/willscott/goturn

package main

import (
	"io/ioutil"
	"log"
	"net"
	"net/http"

	"github.com/willscott/goturn/client"
)

func main() {
	// Connect to the stun/turn server
	conn, err := net.Dial("tcp", "127.0.0.1:19302")
	if err != nil {
		log.Fatal("error dialing TURN server: ", err)
	}
	defer conn.Close()

	credentials := client.LongtermCredentials("username", "password")
	dialer, err := client.NewDialer(&credentials, conn)
	if err != nil {
		log.Fatal("failed to obtain dialer: ", err)
	}

	httpClient := &http.Client{Transport: &http.Transport{Dial: dialer.Dial}}
	httpResp, err := httpClient.Get("http://www.google.com/")
	if err != nil {
		log.Fatal("error performing http request: ", err)
	}
	defer httpResp.Body.Close()

	httpBody, err := ioutil.ReadAll(httpResp.Body)
	if err != nil {
		log.Fatal("error reading http response: ", err)
	}
	log.Printf("received %d bytes", len(httpBody))
}