SimpleEventBroker.cs

public interface IEventBroker
{
  Task Publish(object e);
}

internal class EventBroker : IEventBroker
{
  private readonly IList<DomainEventHandler> _handlers;
  public EventBroker(IList<DomainEventHandler> subscribers)
  {
    _handlers = subscribers;
  }

  public async Task Publish(object e)
  {
    foreach (var handler in _handlers)
    { 
      await handler.Handle(e);
    }
  }
}

public abstract class DomainEventHandler
{
  public async Task Handle(object it)
  {
    if (await WantToHandle(it))
    {
      await ThenHandle(it);
    }
  }

  protected abstract Task<bool> WantToHandle(object it);
  protected abstract Task ThenHandle(object it);
}