public static void Main()

        {

            Console.WriteLine(Thread.CurrentThread.ManagedThreadId);

            In();

            Console.WriteLine("run after in");

            Console.Read();

        }

        public static async void In()

        {

            var name=Name();

            Console.WriteLine(Thread.CurrentThread.ManagedThreadId);

            Console.WriteLine("{0} run in {1}",Thread.CurrentThread.ManagedThreadId, await name );

            Console.WriteLine(Thread.CurrentThread.ManagedThreadId);

        }

        public static async Task<string> Name()

        {

            var res = Task.Run(() => {

                Thread.Sleep();

                Console.WriteLine("Child is {0}",Thread.CurrentThread.ManagedThreadId);

                return "jacket";

            });

            return await res;

        }

run after in //整个顺序是Main->In->Name,然后在Name返回处直接跳出，执行var name=Name();下面代码，执行下去后遇到await name再次跳出，执行In()下方代码其他代码由Task线程执行。首先await的使用是最外层一定要套一个async函数，个人认为保证了不会跳出Main（）函数。

Child is

 run in jacket //Console.WriteLine("{0} run in {1}",await name，Thread.CurrentThread.ManagedThreadId);的执行结果是jacket run in 1.说明同一语句都能拆分到不同线程里执行啊