package main

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

func main() {
    http.HandleFunc("/hello", hello)
    http.ListenAndServe(":8080", nil)
}

func hello(w http.ResponseWriter, r *http.Request) {
    s := time.Now()
    fmt.Println("Start: ", s)

    time.Sleep(15 * time.Second)
    w.Write([]byte("hello!"))

    e := time.Now()
    fmt.Println("Stop: ", e)
}

/* Output for the request run at same time
Start:  2016-01-08 18:20:23.205378808 +0100 CET
Stop:  2016-01-08 18:20:38.208704065 +0100 CET
Start:  2016-01-08 18:20:38.210874469 +0100 CET
Stop:  2016-01-08 18:20:53.21145758 +0100 CET
*/