static void AsyncSrv_ServerTask(ZContext context) 
		{
			// This is our server task.
			// It uses the multithreaded server model to deal requests out to a pool
			// of workers and route replies back to clients. One worker can handle
			// one request at a time but one client can talk to multiple workers at
			// once.

			using (var frontend = new ZSocket(context, ZSocketType.ROUTER))
			using (var backend = new ZSocket(context, ZSocketType.DEALER))
			{
				// Frontend socket talks to clients over TCP
				frontend.Bind("tcp://*:5570");
				// Backend socket talks to workers over inproc
				backend.Bind("inproc://backend");

				// Launch pool of worker threads, precise number is not critical
				for (int i = 0; i < 5; ++i)
				{
					int j = i; new Thread(() => AsyncSrv_ServerWorker(context, j)).Start();
				}

				// Connect backend to frontend via a proxy
				ZError error;
				if (!ZContext.Proxy(frontend, backend, out error))
				{
					if (error == ZError.ETERM)
						return;	// Interrupted
					throw new ZException(error);
				}
			}
		}

        static void Espresso0_Listener(ZContext context)
        {
            // The listener receives all messages flowing through the proxy, on its
            // pipe. In CZMQ, the pipe is a pair of ZMQ_PAIR sockets that connect
            // attached child threads. In other languages your mileage may vary:

            using (var listener = new ZSocket(context, ZSocketType.PAIR))
            {
                listener.Connect("inproc://listener");

                //Print everything that arrives on pipe
                ZError error;
                ZFrame frame;
                while (true)
                {
                    if (null == (frame = listener.ReceiveFrame(out error)))
                    {
                        if (error == ZError.ETERM)
                            return; // Interrupted
                        throw new ZException(error);
                    }
                    using (frame)
                        frame.DumpZfrm();
                }
            }
        }

		// Basic request-reply client using REQ socket
		static void LBBroker_Client(ZContext context, int i)
		{
			// Create a socket
			using (var client = new ZSocket(context, ZSocketType.REQ))
			{
				// Set a printable identity
				client.IdentityString = "CLIENT" + i;

				// Connect
				client.Connect("inproc://frontend");

				using (var request = new ZMessage())
				{
					request.Add(new ZFrame("Hello"));

					// Send request
					client.Send(request);
				}

				// Receive reply
				using (ZMessage reply = client.ReceiveMessage())
				{
					Console.WriteLine("CLIENT{0}: {1}", i, reply[0].ReadString());
				}
			}
		}

		static ZFrame FLClient1_TryRequest(ZContext context, string endpoint, ZFrame request)
		{
			Console.WriteLine("I: trying echo service at {0}...", endpoint);

			using (var client = new ZSocket(context, ZSocketType.REQ))
			{
				client.Connect(endpoint);

				// Send request, wait safely for reply
				using (var message = ZFrame.CopyFrom(request))
				{
					client.Send(message);
				}

				var poll = ZPollItem.CreateReceiver();
				ZError error;
				ZMessage incoming;

				if (client.PollIn(poll, out incoming, out error, FLClient1_REQUEST_TIMEOUT))
				{
					return incoming[0];
				}
			}
			return null;
		}

        //  Round-trip demonstrator
        //  While this example runs in a single process, that is just to make
        //  it easier to start and stop the example. The client task signals to
        //  main when it's ready.
        public static void Tripping(string[] args)
        {
            bool verbose = (args.Any(e => e.ToLower().Equals("-v")
                                          || e.ToLower().Equals("--verbose")));
            Console.WriteLine("Verbose: {0}", verbose);

            CancellationTokenSource cancellor = new CancellationTokenSource();
            Console.CancelKeyPress += (s, ea) =>
            {
                ea.Cancel = true;
                cancellor.Cancel();
            };

            using (ZContext ctx = new ZContext())
            {
                using (var client = new ZActor(ctx, Tripping_ClientTask))
                {
                    (new Thread(() => Tripping_WorkerTask(ctx))).Start();
                    (new Thread(() => Tripping_BrokerTask(ctx))).Start();
                    client.Start();
                    using (var signal = client.Frontend.ReceiveFrame())
                        if (verbose)
                            signal.ToString().DumpString();
                }
            }
        }

        public static void TaskWork(string[] args)
        {
            //
            // Task worker
            // Connects PULL socket to tcp://127.0.0.1:5557
            // Collects workloads from ventilator via that socket
            // Connects PUSH socket to tcp://127.0.0.1:5558
            // Sends results to sink via that socket
            //
            // Author: metadings
            //

            // Socket to receive messages on and
            // Socket to send messages to
            using (var context = new ZContext())
            using (var receiver = new ZSocket(context, ZSocketType.PULL))
            using (var sink = new ZSocket(context, ZSocketType.PUSH))
            {
                receiver.Connect("tcp://127.0.0.1:5557");
                sink.Connect("tcp://127.0.0.1:5558");

                // Process tasks forever
                while (true)
                {
                    var replyBytes = new byte[4];
                    receiver.ReceiveBytes(replyBytes, 0, replyBytes.Length);
                    int workload = BitConverter.ToInt32(replyBytes, 0);
                    Console.WriteLine("{0}.", workload);	// Show progress

                    Thread.Sleep(workload);	// Do the work

                    sink.Send(new byte[0], 0, 0);	// Send results to sink
                }
            }
        }

		public static void PSEnvSub(string[] args)
		{
			//
			// Pubsub envelope subscriber
			//
			// Author: metadings
			//

			// Prepare our context and subscriber
			using (var context = new ZContext())
			using (var subscriber = new ZSocket(context, ZSocketType.SUB))
			{
				subscriber.Connect("tcp://127.0.0.1:5563");
				subscriber.Subscribe("B");

				int subscribed = 0;
				while (true)
				{
					using (ZMessage message = subscriber.ReceiveMessage())
					{
						subscribed++;

						// Read envelope with address
						string address = message[0].ReadString();

						// Read message contents
						string contents = message[1].ReadString();

						Console.WriteLine("{0}. [{1}] {2}", subscribed, address, contents);
					}
				}
			}
		}

		public ZActor(ZContext context, ZAction action, params object[] args)
			: this(context, default(string), action, args)
		{
			var rnd0 = new byte[8];
			using (var rng = new System.Security.Cryptography.RNGCryptoServiceProvider()) rng.GetNonZeroBytes(rnd0);
			this.Endpoint = string.Format("inproc://{0}", ZContext.Encoding.GetString(rnd0));
		}

        public static void PSEnvPub(string[] args)
        {
            //
            // Pubsub envelope publisher
            //
            // Author: metadings
            //

            // Prepare our context and publisher
            using (var context = new ZContext())
            using (var publisher = new ZSocket(context, ZSocketType.PUB))
            {
                publisher.Linger = TimeSpan.Zero;
                publisher.Bind("tcp://*:5563");

                while (true)
                {
                    // Write two messages, each with an envelope and content
                    using (var message = new ZMessage())
                    {
                        message.Add(new ZFrame("A"));
                        message.Add(new ZFrame("We don't want to see this"));
                        publisher.Send(message);
                    }
                    using (var message = new ZMessage())
                    {
                        message.Add(new ZFrame("B"));
                        message.Add(new ZFrame("We would like to see this"));
                        publisher.Send(message);
                    }
                    Thread.Sleep(1000);
                }
            }
        }

		static void Espresso_Publisher(ZContext context) 
		{
			// The publisher sends random messages starting with A-J:

			using (var publisher = new ZSocket(context, ZSocketType.PUB))
			{
				publisher.Bind("tcp://*:6000");

				ZError error;

				while (true)
				{
					var bytes = new byte[5];
					using (var rng = new System.Security.Cryptography.RNGCryptoServiceProvider())
					{
						rng.GetBytes(bytes);
					}

					if (!publisher.SendBytes(bytes, 0, bytes.Length, ZSocketFlags.None, out error))
					{
						if (error == ZError.ETERM)
							return;	// Interrupted
						throw new ZException(error);
					}

					Thread.Sleep(1);
				}
			}
		}

		static void Espresso_Subscriber(ZContext context) 
		{
			// The subscriber thread requests messages starting with
			// A and B, then reads and counts incoming messages.

			using (var subscriber = new ZSocket(context, ZSocketType.SUB))
			{
				subscriber.Connect("tcp://127.0.0.1:6001");
				subscriber.Subscribe("A");
				subscriber.Subscribe("B");

				ZError error;
				int count = 0;
				while (count < 5)
				{
					var bytes = new byte[10];
					int bytesLength;
					if (-1 == (bytesLength = subscriber.ReceiveBytes(bytes, 0, bytes.Length, ZSocketFlags.None, out error)))
					{
						if (error == ZError.ETERM)
							return;	// Interrupted
						throw new ZException(error);
					}

					++count;
				}

				Console.WriteLine("I: subscriber counted {0}", count);
			}
		}

        static void Main(string[] args)
        {
            var queueAddress = Config.Get("Queues.Fulfilment.Address");

            using (var context = new ZContext())
            using (var receiver = new ZSocket(context, ZSocketType.PULL))
            {
                receiver.Bind(queueAddress);
                Console.WriteLine("Listening for messages on: " + queueAddress);

                while (true)
                {
                    using (var message = receiver.ReceiveMessage())
                    {
                        var headerFrame = message.First();
                        var header = JsonConvert.DeserializeObject<Header>(headerFrame.ReadString());
                        Console.WriteLine("* Received message, ID: {0}, body type: {1}, handled count: {2}", header.MessageId, header.BodyType, header.HandledCount);

                        //assume this is a permanent failure
                        if (header.HandledCount < 3)
                        {
                            Console.WriteLine("** Handling message. Previous attempts: {0}", header.HandledCount);
                            Handle(header, message.ElementAt(1));
                        }
                        else
                        {
                            Console.WriteLine("!! Message has failed {0} times. Not processing. Last exception: {1}", header.HandledCount, header.LastExceptionMessage);
                            //TODO - forward to error queue
                        }
                    }
                    Thread.Sleep(100);
                }
            }
        }

		static void Espresso_Subscriber(ZContext context) 
		{
			// The subscriber thread requests messages starting with
			// A and B, then reads and counts incoming messages.

			using (var subscriber = new ZSocket(context, ZSocketType.SUB))
			{
				subscriber.Connect("tcp://127.0.0.1:6001");
				subscriber.Subscribe("A");
				subscriber.Subscribe("B");

				ZError error;
				ZFrame frame;
				int count = 0;
				while (count < 5)
				{
					if (null == (frame = subscriber.ReceiveFrame(out error)))
					{
						if (error == ZError.ETERM)
							return;	// Interrupted
						throw new ZException(error);
					}

					++count;
				}

				Console.WriteLine("I: subscriber counted {0}", count);
			}
		}

        public static void Main(string[] args)
        {
            //
            // Multithreaded Hello World server
            //
            // Author: metadings
            //

            // Socket to talk to clients and
            // Socket to talk to workers
            using (var ctx = new ZContext())
            using (var clients = new ZSocket(ctx, ZSocketType.ROUTER))
            using (var workers = new ZSocket(ctx, ZSocketType.DEALER))
            {
                clients.Bind("tcp://*:5555");
                workers.Bind("inproc://workers");

                // Launch pool of worker threads
                for (int i = 0; i < 5; ++i)
                {
                    new Thread(() => MTServer_Worker(ctx)).Start();
                }

                // Connect work threads to client threads via a queue proxy
                ZContext.Proxy(clients, workers);
            }
        }

        public TaskWorker(string workerid="*",string SenderIP = "127.0.0.1", int SenderPort = 5557, string sinkIP = "127.0.0.1", int sinkPort=5558)
        {
            //
            // Task worker
            // Connects PULL socket to tcp://localhost:5557
            // Collects workloads from ventilator via that socket
            // Connects PUSH socket to tcp://localhost:5558
            // Sends results to sink via that socket
            //
            // Author: metadings
            //

            // Socket to receive messages on and
            // Socket to send messages to
            using (var context = new ZContext())
            using (var receiver = new ZSocket(context, ZSocketType.PULL))
            using (var sink = new ZSocket(context, ZSocketType.PUSH))
            {
                receiver.Connect(String.Format ("tcp://{0}:{1}",SenderIP,SenderPort));
                sink.Connect(string.Format("tcp://{0}:{1}",sinkIP,sinkPort ));
                Console.WriteLine("Worker " + workerid + " ready.");
                // Process tasks forever
                while (true)
                {
                    var replyBytes = new byte[4];
                    receiver.ReceiveBytes(replyBytes, 0, replyBytes.Length);
                    int workload = BitConverter.ToInt32(replyBytes, 0);
                    Console.WriteLine("{0}.", workload);    // Show progress

                    Thread.Sleep(workload);    // Do the work

                    sink.Send(new byte[0], 0, 0);    // Send results to sink
                }
            }
        }

        private static void Handle(Header header, ZFrame bodyFrame)
        {
            //TODO - really we'd have a message handler factory:
            if (header.BodyType == typeof(SendFulfilmentCommand).Name)
            {
                var command = JsonConvert.DeserializeObject<SendFulfilmentCommand>(bodyFrame.ReadString());
                var client = FulfilmentClientFactory.GetApiClient(command.FulfilmentType);
                try
                {
                    client.Send(command.Address);
                    Console.WriteLine("*** Sent fulfilment, type: {0}, to address: {1}", command.FulfilmentType, command.Address);
                }
                catch (Exception ex)
                {
                    Console.WriteLine("*** Fulfilment failed, resending message");

                    var queueAddress = Config.Get("Queues.Fulfilment.Address");
                    header.HandledCount++;
                    header.LastExceptionMessage = ex.Message;

                    var messageFrames = new List<ZFrame>();
                    messageFrames.Add(new ZFrame(JsonConvert.SerializeObject(header)));
                    messageFrames.Add(bodyFrame);

                    using (var context = new ZContext())
                    using (var sender = new ZSocket(context, ZSocketType.PUSH))
                    {
                        sender.Connect(queueAddress);
                        sender.Send(new ZMessage(messageFrames));
                    }
                }
            }
        }

		static void RTReq_Worker(int i) 
		{
			using (var context = new ZContext())
			using (var worker = new ZSocket(context, ZSocketType.REQ))
			{
				worker.IdentityString = "PEER" + i;	// Set a printable identity
				worker.Connect("tcp://127.0.0.1:5671");

				int total = 0;
				while (true)
				{
					// Tell the broker we're ready for work
					worker.Send(new ZFrame("Hi Boss"));

					// Get workload from broker, until finished
					using (ZFrame frame = worker.ReceiveFrame())
					{
						bool finished = (frame.ReadString() == "Fired!");
						if (finished)
						{
							break;
						}
					}

					total++;

					// Do some random work
					Thread.Sleep(1);
				}

				Console.WriteLine("Completed: PEER{0}, {1} tasks", i, total);
			}
		}

		// The subscriber thread requests messages starting with
		// A and B, then reads and counts incoming messages.
		static void Espresso0_Subscriber(ZContext context) 
		{
			// Subscrie to "A" and "B"
			using (var subscriber = new ZSocket(context, ZSocketType.SUB))
			{
				subscriber.Connect("tcp://127.0.0.1:6001");
				subscriber.Subscribe("A");
				subscriber.Subscribe("B");

				ZError error;
				ZFrame frm;
				int count = 0;
				while (count < 5)
				{
					if (null == (frm = subscriber.ReceiveFrame(out error)))
					{
						if (error == ZError.ETERM)
							return;	// Interrupted
						throw new ZException(error);
					}
					++count;
				}

				Console.WriteLine("I: subscriber counted {0}", count);
			}
		}

		public static void RRClient(string[] args)
		{
			//
			// Hello World client
			// Connects REQ socket to tcp://localhost:5559
			// Sends "Hello" to server, expects "World" back
			//
			// Author: metadings
			//

			// Socket to talk to server
			using (var context = new ZContext())
			using (var requester = new ZSocket(context, ZSocketType.REQ))
			{
				requester.Connect("tcp://127.0.0.1:5559");

				for (int n = 0; n < 10; ++n)
				{
					requester.Send(new ZFrame("Hello"));

					using (ZFrame reply = requester.ReceiveFrame())
					{
						Console.WriteLine("Hello {0}!", reply.ReadString());
					}
				}
			}
		}

        public static void Espresso(string[] args)
        {
            //
            // Espresso Pattern
            // This shows how to capture data using a pub-sub proxy
            //
            // Author: metadings
            //

            using (var context = new ZContext())
            using (var subscriber = new ZSocket(context, ZSocketType.XSUB))
            using (var publisher = new ZSocket(context, ZSocketType.XPUB))
            using (var listener = new ZSocket(context, ZSocketType.PAIR))
            {
                new Thread(() => Espresso_Publisher(context)).Start();
                new Thread(() => Espresso_Subscriber(context)).Start();
                new Thread(() => Espresso_Listener(context)).Start();

                subscriber.Connect("tcp://127.0.0.1:6000");
                publisher.Bind("tcp://*:6001");
                listener.Bind("inproc://listener");

                ZError error;
                if (!ZContext.Proxy(subscriber, publisher, listener, out error))
                {
                    if (error == ZError.ETERM)
                        return;	// Interrupted
                    throw new ZException(error);
                }
            }
        }