Async parallel processing

AsyncParallel.cs

var runningTasks = new ConcurrentDictionary<Task, string>();
var maxDegreeOfParallelism = 5;
var semaphore = new SemaphoreSlim(maxDegreeOfParallelism);

foreach (var job in jobs)
{
    await semaphore.WaitAsync();

    var task = ProcessAsync(job);
    runningTasks.TryAdd(task, "");

    await task.ContinueWith(t =>
    {
        runningTasks.TryRemove(t, out _);
        semaphore.Release();
    });
}

await Task.WhenAll(runningTasks.Keys.ToArray());