IO绑定的异步任务不是异步执行的(IO-bound async task not executes asynchronously)

 我花了很多时间来理解异步编程原理。 但有一点仍不清楚。 我被这段代码搞糊涂了： 
 
    static async Task Method()
    {
        Console.WriteLine($"Method entered.");

        await Task.Delay(1000);
        Console.WriteLine($"Await 1 finished.");

        await Task.Delay(1000);
        Console.WriteLine($"Await 2 finished");
    }

    static int Main(string[] args)
    {
        Console.WriteLine($"Main started.");

        return AsyncContext.Run(() => MainAsync(args));
    }

    static async Task<int> MainAsync(string[] args)
    {
        var t = Method();
        Console.WriteLine("Thread starting sleep.");
        Thread.Sleep(10000);
        Console.WriteLine("Thread stopped sleeping");
        Console.WriteLine(t.IsCompleted ? "Method completed" : "Method not completed");
        await t;
        return 0;
    }
 
 结果： 
 
Main started.
Method entered.
Thread starting sleep.
Thread stopped sleeping
Method not completed
Await 1 finished.
Await 2 finished
 
 据我所知，当主线程处于休眠状态时，应执行来自Method的IO绑定操作（导致Task.Delay模拟IO）并按顺序中断主线程以继续执行方法代码。 所以我希望看到： 
 
Main started.
Method entered.
Thread starting sleep.
Await 1 finished.
Await 2 finished
Thread stopped sleeping
Method completed
 
 我知道通过Thread.Sleep我正在制作停止主线程。 但据我所知，Method（）不应该需要线程，因为它包含IO绑定操作。 任何人都能解释我误解的地方吗？ 
 
 我正在使用的AsynContext是（ 这里 ）。 

I has spend a lot of time to understand async programming principles. But one thing is still unclear. I was confused by this code : 
 
    static async Task Method()
    {
        Console.WriteLine($"Method entered.");

        await Task.Delay(1000);
        Console.WriteLine($"Await 1 finished.");

        await Task.Delay(1000);
        Console.WriteLine($"Await 2 finished");
    }

    static int Main(string[] args)
    {
        Console.WriteLine($"Main started.");

        return AsyncContext.Run(() => MainAsync(args));
    }

    static async Task<int> MainAsync(string[] args)
    {
        var t = Method();
        Console.WriteLine("Thread starting sleep.");
        Thread.Sleep(10000);
        Console.WriteLine("Thread stopped sleeping");
        Console.WriteLine(t.IsCompleted ? "Method completed" : "Method not completed");
        await t;
        return 0;
    }
 
Result :
 
Main started.
Method entered.
Thread starting sleep.
Thread stopped sleeping
Method not completed
Await 1 finished.
Await 2 finished
 
As I understand while Main thread is sleeping IO-bound operations from Method should be executed (cause Task.Delay emulate IO) and interrupt Main thread sequentially to continue execute Method code. So I expect to see:
 
Main started.
Method entered.
Thread starting sleep.
Await 1 finished.
Await 2 finished
Thread stopped sleeping
Method completed
 
I know that by Thread.Sleep I am making to stop Main thread. But as I understand Method() should not need thread because it consists of IO-bound operations. Can anybody explain where I am misunderstanding it?
 
AsynContext that I am using is (here).

原文：https://stackoverflow.com/questions/43469076