C#中的CancellationTokenSource類可以通過CancelAfter方法設定超時時間，因此可以用於非同步方法中的超時設定。

測試程式碼：

class Program
{
    static async Task Main(string[] args)
    {
        using (var tokenSource = new CancellationTokenSource())
        {
            //設定超時時間
            tokenSource.CancelAfter(1000);

            var stopWatch = new
 
 Stopwatch();
            stopWatch.Start();
            await SampleFunctionAsync(tokenSource.Token);
            stopWatch.Stop();

            if (tokenSource.Token.IsCancellationRequested)
            {
                Console.WriteLine(@"IsCancellationRequested");
            }

            Console.WriteLine($
 
"SampleFunctionAsync takes {stopWatch.ElapsedMilliseconds}ms.");
        }

        Console.ReadKey();
    }

    private static async Task SampleFunctionAsync(CancellationToken token)
    {
        try
        {
            await Task.Delay(2000, token);
        }
        catch (Exception e)
        {
            Console.WriteLine($
 
@"SampleFunctionAsync exception: {e.Message}");
        }
    }
}

測試結果：