Client.cs

public class Client : MonoBehaviour
{
    private SubscriberSocket m_subscriber;
    private NetMQContext m_context;
    
    // Use this for initialization
    void Start()
    {        
        ForceDotNet.Force();        

        m_context = NetMQContext.Create();
        m_subscriber = m_context.CreateSubscriberSocket();
        m_subscriber.Options.Linger = TimeSpan.Zero;
        m_subscriber.Subscribe("");
        m_subscriber.Connect("tcp://127.0.0.1:55561");        
        
        Debug.Log("Connected");
    }
   
    // Update is called once per frame
    void Update()
    {
        string message;        

        while (m_subscriber.TryReceiveFrameString(out message))
        {
            Debug.Log("Received");
        }        
    }

    void OnApplicationQuit()
    {
        m_subscriber.Dispose();
        m_context.Dispose();
        Debug.Log("Exit");
    }
}

Server.cs

public class Server : MonoBehaviour {

    private NetMQContext m_context;
    private PublisherSocket m_publisher;
    private int m_count = 0;

    // Use this for initialization
    void Start () {
        ForceDotNet.Force();

        m_context = NetMQContext.Create();
        m_publisher = m_context.CreatePublisherSocket();
        m_publisher.Options.Linger = TimeSpan.Zero;
        m_publisher.Bind("tcp://127.0.0.1:55561");        

        Debug.Log("Bound");        
    }
	
	// Update is called once per frame
	void Update () {
        m_count++;

        if (m_count % 200 == 0)
        {
            m_publisher.SendFrame(m_count.ToString());
            Debug.Log("Published");
        }
    }

    void OnApplicationQuit()
    {
        m_publisher.Dispose();
        m_context.Dispose();
        Debug.Log("Exit");
    }
}