Hello World Handler with sleep

main.go

package main

import (
	"net/http"
	"time"
)

func main() {
	http.ListenAndServe(":3000", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		time.Sleep(200 * time.Millisecond)
		w.Write([]byte("Hello World"))
	}))
}