NuExt.System's ReentrantAsyncLock also works

[matthew-a-thomas]

https://github.com/IvanGit/NuExt.System/blob/71dee735da6603adfc8b08bd24c55d81d78f2d71/src/System/Threading/ReentrantAsyncLock.cs

using var asyncLock = new ReentrantAsyncLock();
for (var i = 0; i < 1000; i++)
{
    var raceCondition = 0;
    // You can acquire the lock asynchronously
    await asyncLock.AcquireAsync(async () =>
    {
        await Task.WhenAll(
            Task.Run(async () =>
            {
                // The lock is reentrant
                await asyncLock.AcquireAsync(async () =>
                {
                    // The lock provides mutual exclusion
                    raceCondition++;
                    await Task.CompletedTask;
                });
            }),
            Task.Run(async () =>
            {
                await asyncLock.AcquireAsync(async () =>
                {
                    raceCondition++;
                    await Task.CompletedTask;
                });
            })
        );
    });
    if (raceCondition != 2)
        throw new Exception();
}

Need to update documentation accordingly.