internal AsyncDelegatingConsumer(
     AsyncNewEventHandler <T> onNew,
     AsyncSuccessfulEventHandler?onAllSucceeded = null,
     AsyncFailedEventHandler?onAnyFailed        = null)
 {
     _onNew          = onNew;
     _onAllSucceeded = onAllSucceeded;
     _onAnyFailed    = onAnyFailed;
 }
 public static IAsyncRillConsumer <T> AsynchronousConsumer <T>(
     AsyncNewEventHandler <T> onNew,
     AsyncSuccessfulEventHandler?onAllSucceeded = null,
     AsyncFailedEventHandler?onAnyFailed        = null)
 => new AsyncDelegatingConsumer <T>(onNew, onAllSucceeded, onAnyFailed);
 public static IDisposable Subscribe <T>(
     this IAsyncRillConsumable <T> consumable,
     AsyncNewEventHandler <T> onNew,
     AsyncSuccessfulEventHandler?onAllSucceeded = null,
     AsyncFailedEventHandler?onAnyFailed        = null)
 => consumable.Subscribe(ConsumerFactory.AsynchronousConsumer(onNew, onAllSucceeded, onAnyFailed));