go tcp http客户端指定本地端口

package main

import (
	"net"
	"time"
)

func main() {

	addr := "127.0.0.1:80"
	netAddr := &net.TCPAddr{Port: 6666}
	d := net.Dialer{LocalAddr: netAddr}
	cc, err := d.Dial("tcp", addr)
	if err != nil {
		return
	}
	for {
		cc.Write([]byte("aaa\n"))
		time.Sleep(time.Second)
	}
}

package main

import (
	"fmt"
	"net"
	"net/http"
	"time"
)

func main() {

	netAddr := &net.TCPAddr{Port: 6667}
	dialer := &net.Dialer{LocalAddr: netAddr}
	tr := &http.Transport{
		Proxy:                 http.ProxyFromEnvironment,
		DialContext:           dialer.DialContext,
		MaxIdleConns:          100,
		IdleConnTimeout:       90 * time.Second,
		TLSHandshakeTimeout:   10 * time.Second,
		ExpectContinueTimeout: 1 * time.Second,
	}

	c := &http.Client{
		Transport: tr,
	}

	url := "https://www.h2check.org/"
	resp, err := c.Get(url)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Printf("%+v\n", resp.Header)
	fmt.Printf("%s\n", resp.Body)
}