using System;

using System.Threading;

using System.Threading.Tasks;

​

static class ReentrantAsyncLockExtensions

{

    public static async Task LockAsync(

        this ReentrantAsyncLock.ReentrantAsyncLock asyncLock,

        Func<Task> whenLocked,

        CancellationToken token)

    {

        await using var _ = await asyncLock.LockAsync(token);

        await whenLocked();

    }

}

​

class Program

{

    static async Task Main()

    {

        var asyncLock = new ReentrantAsyncLock.ReentrantAsyncLock();

        var mutualExclusionTest = 0;

        for (long i = 1;; i++)

        {

            await Task.WhenAll(

                Go(),

                Go(),

                Go(),

                Go(),

                Go()

            );

            if (mutualExclusionTest != 0)

            {

                Console.WriteLine($"There was a mutual exclusion violation on try {i:N0}");

                return;

            }

            if (i % 100_000 == 0 && i > 0)

            {

                Console.WriteLine($"So far so good after try {i:N0}");

            }

        }

​

        Task Go() =>

            asyncLock.LockAsync(async () =>

            {

                // The following two lines are equivalent to the effects of .ConfigureAwait(false)

                SynchronizationContext.SetSynchronizationContext(null);

                await Task.Yield();

​

                var reenterTask = asyncLock.LockAsync(

                    () =>

                    {

                        // If mutual exclusion is preserved then the following two lines will have no net effect

                        mutualExclusionTest++;

                        mutualExclusionTest--;

                        return Task.CompletedTask;

                    },

                    CancellationToken.None

                );

​

                // If mutual exclusion is preserved then the following two lines will have no net effect

                mutualExclusionTest++;

                mutualExclusionTest--;

​

                await reenterTask;

            }, CancellationToken.None);

    }

}