verify Shutdown() and ListenAndServe behavior.

server.go

package main

import (
    "context"
    "log"
    "net/http"
    "time"
)

func delayedHandler(w http.ResponseWriter, r *http.Request) {
    time.Sleep(5 * time.Second)
    w.Write([]byte("i'm slow"))
}

func main() {
    var server http.Server
    server.Handler = http.HandlerFunc(delayedHandler)
    server.Addr = ":8080"

    waitCh := make(chan struct{})

    go func() {
        err := server.ListenAndServe()
        log.Printf("server.ListenAndServe exited: %v", err)
        close(waitCh)
    }()

    time.Sleep(time.Second)

    go func() {
        http.Get("http://localhost:8080")
    }()

    time.Sleep(100 * time.Millisecond)

    err := server.Shutdown(context.Background())
    log.Printf("server.Shutdown exited: %v", err)

    <-waitCh
}