public static class TaskHelper
{

    // 有返回值
    public static async Task<TResult> TimeoutAfter<TResult>(this Task<TResult> task, TimeSpan timeout)
    {
        using (var timeoutCancellationTokenSource = new CancellationTokenSource())
        {
            var completedTask = await Task.WhenAny(task, Task.Delay(timeout, timeoutCancellationTokenSource.Token));
            if (completedTask == task)
            {
                timeoutCancellationTokenSource.Cancel();
                return await task;  // Very important in order to propagate exceptions
            }
            else
            {
                throw new TimeoutException("The operation has timed out.");
            }
        }
    }

    // 無返回值
    public static async Task TimeoutAfter(this Task task, TimeSpan timeout)
    {
        using (var timeoutCancellationTokenSource = new CancellationTokenSource())
        {
            var completedTask = await Task.WhenAny(task, Task.Delay(timeout, timeoutCancellationTokenSource.Token));
            if (completedTask == task)
            {
                timeoutCancellationTokenSource.Cancel();
                await task;  // Very important in order to propagate exceptions
            }
            else
            {
                throw new TimeoutException("The operation has timed out.");
            }
        }
    }
}

    [TestMethod]
    public async Task TestMethod1()
    {
        //A 任務(wù)必須在指定時(shí)間內(nèi)完成,否則任務(wù)失敗
        //A 任務(wù)依賴B,C任務(wù),B,C可以并行,任何一個(gè)失敗,則A任務(wù)失敗
        //A任務(wù)
        try
        {
            //有效時(shí)間3s
            var timeOut = TimeSpan.FromSeconds(3);
            await Task.Run(async () =>
            {
                List<Task<(string, bool)>> tasks = new List<Task<(string, bool)>>();
                //B任務(wù)
                tasks.Add(Task.Run(async () =>
                {
                    return ("B", await TestTask("B"));
                }).TimeoutAfter(timeOut));

                //C任務(wù)
                tasks.Add(Task.Run(async () =>
                {
                    return ("C", await TestTask("C"));
                }).TimeoutAfter(timeOut));

                var res = await Task.WhenAll(tasks);

                //兩個(gè)任務(wù),任何一個(gè)失敗,則A任務(wù)失敗
                foreach (var item in res)
                {
                    Console.WriteLine(item);
                }

            }).TimeoutAfter(timeOut);

        }
        catch (Exception ex)
        {
            Console.WriteLine("A任務(wù)執(zhí)行超時(shí)了");
        }

        //await Task.Delay(3000);


    }

    public async Task<bool> TestTask(string name) 
    {
        var startTime = DateTime.Now;
        Console.WriteLine($"{startTime}---->{name}任務(wù)開始執(zhí)行");
        //隨機(jī)堵塞1-5s
        var t = new Random().Next(1, 5);
        await Task.Delay(t * 1000);

        var endTime = DateTime.Now; ;
        var time = (endTime - startTime).TotalSeconds;

        //隨機(jī)數(shù),模擬業(yè)務(wù)是否成功
        var res = new Random().Next(1, 10);
        Console.WriteLine($"{endTime}---->{name}任務(wù)執(zhí)行完畢,耗時(shí){time} s");
        return res <= 7;
    }