using System;

using System.Threading;

using System.Threading.Tasks;

​

public static class Program

{

    public static async Task Main()

    {

        try

        {

            async ValueTask<int> MyMethod1(CancellationToken token)

            {

                token.ThrowIfCancellationRequested();

                //...

                await Task.CompletedTask;

                return 13;

            }

​

            ValueTask<int> task = MyMethod1(new CancellationToken(true));

            Console.Write($"MyMethod1, IsCanceled: {task.IsCanceled}, "); // True

            await task; // throws OperationCanceledException

        }

        catch (Exception ex) { Console.WriteLine(ex.GetType().Name); }

​

        try

        {

            ValueTask<int> MyMethod2(CancellationToken token)

            {

                if (token.IsCancellationRequested)

                    return new ValueTask<int>(Task.FromCanceled<int>(token));

                //...

                return new ValueTask<int>(13);

            }

​

            ValueTask<int> task = MyMethod2(new CancellationToken(true));

            Console.Write($"MyMethod2, IsCanceled: {task.IsCanceled}, "); // True

            await task; // throws TaskCanceledException

        }

        catch (Exception ex) { Console.WriteLine(ex.GetType().Name); }

​

        try

        {

            ValueTask<int> MyMethod3(CancellationToken token)

            {

                if (token.IsCancellationRequested)

                    return new ValueTask<int>(

                        Task.FromException<int>(new OperationCanceledException(token)));

                //...

                return new ValueTask<int>(13);

            }

​

            ValueTask<int> task = MyMethod3(new CancellationToken(true));

            Console.Write($"MyMethod3, IsCanceled: {task.IsCanceled}, "); // False

            await task; // throws OperationCanceledException

        }

        catch (Exception ex) { Console.WriteLine(ex.GetType().Name); }

    }

}

​