class Program
    {
        //Delegate
        private delegate int BinaryOperation(int x, int y);

        static void Main(string[] args)
        {
            //Current Thread
            Console.WriteLine("Add() anropas på tråd " + Thread.CurrentThread.ManagedThreadId.ToString());

            //Create delegate
            BinaryOperation b = new BinaryOperation(Add);

            //Call delegate async and save values
            IAsyncResult i= b.BeginInvoke(10, 10, null, null);

            //No waiting time
            do
            {
                Console.WriteLine("Waiting...");
                Thread.Sleep(500);

            }
            while (!i.IsCompleted);

            //Waiting until BeginInvoke is finished
            int answer = b.EndInvoke(i);

            //Output
            Console.WriteLine("10+10 = "+answer);
        }

        static int Add(int x, int y)
        {
            //Skriv ut aktuell tråd
            Console.WriteLine("Add() anropas på tråd " + Thread.CurrentThread.ManagedThreadId.ToString());

            //Sleep
            Thread.Sleep(2000);

            //Return summan
            return x + y;
        }
    }