SemaphoreSlim Sınıfı

Constructor
Şöyle yaparız.

public static Task ForEachAsync<TIn>(
            IEnumerable<TIn> inputEnumerable,
            Func<TIn, Task> asyncProcessor,
            int? maxDegreeOfParallelism = null)
{
  int maxAsyncThreadCount = maxDegreeOfParallelism ?? DefaultMaxDegreeOfParallelism;
  SemaphoreSlim throttler = new SemaphoreSlim(maxAsyncThreadCount, maxAsyncThreadCount);

  IEnumerable<Task> tasks = inputEnumerable.Select(async input =>
  {
    await throttler.WaitAsync().ConfigureAwait(false);
    try
    {
      await asyncProcessor(input).ConfigureAwait(false);
    }
    finally
    {
      throttler.Release();
    }
  });
  return Task.WhenAll(tasks);
}