This is just an enhancement for proxy
based on source of https://github.com/zeromq/netmq/blob/master/src/NetMQ/Proxy.cs
1. define your own:
public Action<IReceivingSocket, IOutgoingSocket> proxyBetweenAction;
2. pass it to constructor:
var frontSocket = new SubscriberSocket(string.Format("@tcp://{0}", frontAddress));
var backSocket = new PublisherSocket(string.Format("@tcp://{0}", backAddress));
((SubscriberSocket)frontSocket).SubscribeToAnyTopic();
proxy1 = new NetmqProxy(frontSocket, backSocket, proxyBetweenAction);
3. that is...