C#异步中的Task,async,await

class Program
{
static void Main(string[] args)
{
Console.WriteLine("我是主线程，线程ID：{0}", Thread.CurrentThread.ManagedThreadId);
TestAsync();
Console.ReadLine();
}

static async void  TestAsync()
{
Console.WriteLine("调用GetReturnResult()之前，线程ID：{0}。当前时间：{1}", Thread.CurrentThread.ManagedThreadId, DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
var name = GetReturnResult();
Console.WriteLine("调用GetReturnResult()之后，线程ID：{0}。当前时间：{1}", Thread.CurrentThread.ManagedThreadId, DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));

//异步回调内容
//在await以及之后的代码都会阻塞
Console.WriteLine("得到GetReturnResult()方法的结果：{0}。当前时间：{1}", await name, DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
Console.WriteLine("await之后的内容。当前时间：{0}",  DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
//异步回调内容
}

static async Task<string> GetReturnResult()
{
Console.WriteLine("执行Task.Run之前, 线程ID：{0}", Thread.CurrentThread.ManagedThreadId);
return await Task.Run(() =>
{
Thread.Sleep(5000);
Console.WriteLine("GetReturnResult()方法里面线程ID: {0}", Thread.CurrentThread.ManagedThreadId);
return "我是返回值";
});
}

}