akka aggregator

class AskAggregator<TReq, TRep> : ReceiveActor
{
    public AskAggregator(IActorRef askFor, IActorRef replyTo, IEnumerable<TReq> items)
    {
        var requestCount = items.Count();
        var replies = new HashSet<TRep>();

        foreach (var request in items) 
            askFor.Tell(request);

        Receive<TRep>(_ => Sender.Equals(askFor), reply =>
        {
            replies.Add(reply);
            requestCount--;

            if (requestCount <= 0)
            {
              replyTo.Tell(new AggregatedReply(replies));
              Context.Stop(Self);
            }
        });
    }
}