Trying to learn about the new async features in c#

Question

I copied this example from here

I have seen many similar examples. Most of them say they're using the Async CTP. I'm using Visual Studio 11 on Windows 8 though so that does not apply. As shown, the error says TaskEx doesn't exist. I assume I'm missing a reference but don't know which one.

This page is http://users.zoominternet.net/~charleswatson/pic.png.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static Random rnd = new Random();

        static void Main(string[] args)
        {
            //Do some other heavy duty background task in this thread
            StartHotel();
            Console.WriteLine("StartHotel called..");
            Console.ReadLine();

        }

        static void StartHotel()
        {
            Console.WriteLine("Starting Hotel..");

            for (int i = 0; i < 10; i++)
            {
                string name = "Chef" + i;
                CookDish(name, "Dish" + i);
                Console.WriteLine("Asked {0} to start cooking at {1}", name, DateTime.Now.ToString());
            }
        }

        static async void CookDish(string chefName, string dish)
        {
            //Induce a random delay 
            int delay = rnd.Next(1000, 4000);
            //Cook is cooking - Task
            await TaskEx.Delay(delay);
            //Write the result - StuffAfterAwait
            Console.WriteLine("Chef {0} Finished at {1}", chefName, DateTime.Now.ToString());
        }
    }
}

Answer 1

In the CTP we were unable to add new features to the Task type so we did the pragmatic thing and just made a new TaskEx type. In the final release there will be no such type; those methods will just be on Task like you'd expect.