static void Main(string[] args)

        {

            Test(); // 这个方法其实是多余的, 本来可以直接写下面的方法

            // await GetName()

            // 但是由于控制台的入口方法不支持async,所有我们在入口方法里面不能 用 await

            Console.WriteLine("Current2 Thread Id :{0}", Thread.CurrentThread.ManagedThreadId);

            Console.ReadKey();

        }

        static async Task Test()

        {

            // 方法打上async关键字，就可以用await调用同样打上async的方法

            // await 后面的方法将在另外一个线程中执行

            await GetName();

        }

        static async Task GetName()

        {

            // Delay 方法来自于.net 4.5

            Console.WriteLine("Current Thread Id :{0}", Thread.CurrentThread.ManagedThreadId);

            //await Task.Delay(1000);  // 返回值前面加 async 之后，方法里面就可以用await了

            var a= Task<string>.Run(() => {

                Console.WriteLine("Current3 Thread Id :{0}", Thread.CurrentThread.ManagedThreadId);

                Thread.Sleep();

                return "abc";

            });

            Console.WriteLine("Current5 Thread Id :{0}", Thread.CurrentThread.ManagedThreadId);

            var b = Task<string>.Run(() =>

            {

                Console.WriteLine("Current4 Thread Id :{0}", Thread.CurrentThread.ManagedThreadId);

                Thread.Sleep();

                return "abc";

            });

            await a;

            Console.WriteLine("Current6 Thread Id :{0}", Thread.CurrentThread.ManagedThreadId);

            await b;

            Console.WriteLine("Current1 Thread Id :{0}", Thread.CurrentThread.ManagedThreadId);

            Console.WriteLine("In antoher thread.....");

        }