多线程和异步

            Func<int, int, int> Add = (a, b) => a + b;

            Thread t = new Thread(() =>
            {
                Console.WriteLine(Add(3,4));
            });
            t.IsBackground = true;
            t.Start();

            Func<int, int, int> Add = (a, b) => a + b;
             
            ThreadPool.QueueUserWorkItem(s =>
            {
                Console.WriteLine(Add(4, 5));
            });

            Func<int, int, int> Add = (a, b) => a + b;

            var result = Add.BeginInvoke(3, 4, null, null);

            Console.WriteLine(Add.EndInvoke(result));

 Func<int, int, int> Add = (a, b) => a + b;
 Add.BeginInvoke(3, 4, myCallBack, Add);

        private void myCallBack(IAsyncResult ar)
        {
            var del = (Func<int, int, int>)ar.AsyncState;
            var res=del.EndInvoke(ar);
            Console.WriteLine(res);
        }