using System;

using System.Threading;

using System.Threading.Tasks;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        AutoResetEvent ev = new AutoResetEvent(false);

        ThreadPool.QueueUserWorkItem(async delegate

        {

            try

            {

                await ThrowException();

            }

            catch (InvalidOperationException)

            {

                Console.WriteLine("IOE 1");

            }

​

            try

            {

                ThrowException().Wait();

            }

            catch (AggregateException)

            {

                Console.WriteLine("AggregateException 1");

            }

​

            try

            {

                string result = ThrowException().Result;

            }

            catch (AggregateException)

            {

                Console.WriteLine("AggregateException 2");

            }

​

            ev.Set();

        }

​

        );

        ev.WaitOne();

    }

​

    public static async Task<string> ThrowException()

    {

        await Task.Delay(5);

        throw new InvalidOperationException("I am invalid!");

        return "foobar";

    }

}