package main

import (
    "log"
    "time"
)

func main() {
    log.Print("started.")

    // 1秒かかるコマンド
    log.Print("sleep1 started.")
    time.Sleep(1 * time.Second)
    log.Print("sleep1 finished.")

    // 2秒かかるコマンド
    log.Print("sleep2 started.")
    time.Sleep(2 * time.Second)
    log.Print("sleep2 finished.")

    // 3秒かかるコマンド
    log.Print("sleep3 started.")
    time.Sleep(3 * time.Second)
    log.Print("sleep3 finished.")

    log.Print("all finished.")
}