C# ZeroMQ no-connected server Request

#define CLRZMQ_3
//#define CLRZMQ_225
//#define CLRZMQ_2

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;

#if(CLRZMQ_225)
using ZMQ;
#elif (CLRZMQ_3 || CLRZMQ_2)
using ZeroMQ;
#endif


namespace _2012_Client_64
{
    class Program
    {
        //Timer check connection
        private static System.Threading.Timer t_NeighConn;

        static void Main(string[] args)
        {
            t_NeighConn = new System.Threading.Timer(neighborsConnection, null, TimeSpan.FromSeconds(0), TimeSpan.FromSeconds(5));

            Console.ReadLine();



        }

        private static void neighborsConnection(object state)
        {
            // number of server to call.
            int numServer = 2;
            for (int i = 0; i < numServer; i++)
            {
                ThreadPool.QueueUserWorkItem(ZeroMqCall, i);
            }
        }

        private static void ZeroMqCall(object state)
        {
            Console.WriteLine(state.ToString());
            try
            {
                 #if(CLRZMQ_225)
            // ZMQ Context and client socket
                using (Context context = new Context())
                using (Socket client = context.Socket(SocketType.REQ))
                {
                    client.Connect("tcp://192.168.1.117:1234");

                    string request = "Hello";

                      Console.WriteLine("Sending request...");
                      client.Send(request, Encoding.UTF8);

                      string reply = client.Recv(Encoding.UTF8);
                      Console.WriteLine("Received reply!!");

            }
                #elif(CLRZMQ_2)

            // ZMQ Context and client socket
                using (var context = ZmqContext.Create())
                using (ZmqSocket client = context.CreateSocket(SocketType.REQ))
                {
                    string _path = "tcp://192.168.3.3:5555";
                    client.Connect(_path);

                    TimeSpan _timeout = new TimeSpan(0,0,0,2000);
                    client.SendTimeout = _timeout;
                    client.ReceiveTimeout = _timeout;
                    client.Linger = new TimeSpan(0, 0, 0);

                    //richiesta
                    Console.WriteLine("Sending");
                    string _parameter = "to send";
                    client.Send(_parameter, Encoding.UTF8, _timeout);

                    // risposta (ritorna null se va in timeout)
                    string reply = client.Receive(Encoding.UTF8, _timeout);

                    if (reply == null)
                        client.Disconnect(_path);


                }


            #elif (CLRZMQ_3)
                using (var context = ZmqContext.Create())
                {
                    using (ZmqSocket client = context.CreateSocket(SocketType.REQ))
                    {

                        // No connected server path
                        string _path = "tcp://192.168.3.12:5555";
                        client.Connect(_path);

                        TimeSpan _timeout = new TimeSpan(0, 0, 0, 0, 1000);

                        //request
                        Console.WriteLine("Sending");

                        SocketFlags sf = SocketFlags.DontWait;

                        System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
                        Byte[] msg = encoding.GetBytes("to send");

                        client.Send(msg, msg.Length, sf, _timeout);
                        /*
                        client.Send("da inviare", Encoding.UTF8, _timeout);

                        // risposta (ritorna null se va in timeout)
                        string reply = client.Receive(Encoding.UTF8, _timeout);
                        Console.WriteLine("Received !!");*/

                        byte[] reply = new byte[4];
                        client.Receive(reply, _timeout);

                        Console.WriteLine("Received !!");

                        client.Close();
                    }
                }
            #endif
            }
            #if(CLRZMQ_225)
            catch (ZMQ.Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            #elif (CLRZMQ_3 || CLRZMQ_2)
                        catch (Exception ex)
                        {
                            Console.WriteLine(ex.Message);
                        }
            #endif
        }
    }
}