using System;
using System.Net;
using System.Diagnostics;
using System.Threading;

namespace Test
{
    static class Program
    {
        [STAThread]
        static void Main()
        {
            bool exit = false;
            WebClient wc = new WebClient();
            DateTime before = DateTime.Now;
            wc.DownloadStringAsync(new Uri("http://74.125.95.147"),"First"); // IP Address of google,so DNS requests don't add to time.
            wc.DownloadStringCompleted += delegate(object sender,DownloadStringCompletedEventArgs e)
            {
                Debug.WriteLine(e.UserState + " Call: " + (DateTime.Now - before));

                if ((string)e.UserState == "First")
                {
                    before = DateTime.Now;
                    wc.DownloadStringAsync(new Uri("http://74.125.95.147"),"Second");
                }
                else
                    exit = true;
            };

            /*
             * 
             * Output:
             * 
             * First Call: 00:00:13.7647873
             * Second Call: 00:00:00.0740042
             * 
             */

            while (!exit)
                Thread.Sleep(1000);
        }
    }
}