demonstrates what happens when transport closes idle connections

badhttp.go

package main

import (
	"context"
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
	"os"
)

func main() {
	client := &http.Client{
		Transport: &http.Transport{
			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
				fmt.Println("dialing")
				d := &net.Dialer{}
				conn, err := d.DialContext(ctx, network, addr)
				if err == nil {
					conn = &loggingConn{conn}
				}
				return conn, err
			},
			MaxIdleConns: -1,
		},
	}

	for i := 0; i < 2; i++ {
		resp, err := client.Get("http://ipecho.net/plain")
		if err != nil {
			log.Fatal(err)
		}
		io.Copy(os.Stdout, resp.Body)
		resp.Body.Close()
		fmt.Println("")
	}
}

type loggingConn struct {
	net.Conn
}

func (conn *loggingConn) Read(b []byte) (int, error) {
	n, err := conn.Conn.Read(b)
	fmt.Printf("read %d: %v\n", n, err)
	return n, err
}