Comment implémenter un arrêt progressif pour un serveur HTTP sous Linux ?

package main

import (
    "fmt"
    "log"
    "net/http"
    "os"
    "os/signal"
)

func main() {
    // Create a new http server.
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "Hello, World!")
    })

    go func() {
        // Start the server.
        log.Fatal(http.ListenAndServe(":8080", nil))
    }()

    // Create a channel to receive os signals.
    sigchan := make(chan os.Signal)
    signal.Notify(sigchan, os.Interrupt)

    // Block until a signal is received.
    <-sigchan

    // Perform shutdown operations.
    log.Println("Shutting down server...")

    // Close the server.
    err := http.CloseServer(http.DefaultServer)
    if err != nil {
        log.Fatal(err)
    }

    // Exit the program.
    os.Exit(0)
}