golang http client using specific network adapter

main.go

package main

import (
	"context"
	"fmt"
	"io/ioutil"
	"net"
	"net/http"
)

func PanicErr(err error) {
	if err != nil {
		panic(err)
	}
}

func main() {

	// Select network adapter that using 192.168.0.50
	// and it will be connect to port 0 (dynamically generate an unused port number)
	addr, err := net.ResolveTCPAddr("tcp", "192.168.0.50:0")
	PanicErr(err)

	dialer := &net.Dialer{LocalAddr: addr}

	dialContext := func(ctx context.Context, network, addr string) (net.Conn, error) {
		conn, err := dialer.Dial(network, addr)
		return conn, err
	}

	transport := &http.Transport{DialContext: dialContext}
	client := &http.Client{
		Transport: transport,
	}

	// http request
	response, err := client.Get("https://api.ipify.org/") // get my IP address
	PanicErr(err)

	data, err := ioutil.ReadAll(response.Body);
	PanicErr(err)

	fmt.Println(string(data))
}