Client.cs

// Clientは Unityを使います
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.Net.Sockets;
using System.IO;
using System.Text;
using System;

public class Application : MonoBehaviour
{
    TcpClient client;
    NetworkStream stream;

    void Start ()
    {
        client = new TcpClient("127.0.0.1", 2001);
        stream = client.GetStream();
    }
    
    public void Poll()
    {
        while (client.Available > 0)
        {
            Command cmd;
            if(TryParseCommand(out cmd))
            {
                commandExec(this, cmd);
            }
        }
    }
    
    bool TryParseCommand(out Command cmd)
    {
        // stream -> Command : 今回は解説しない
        return true;
    }

    void Update ()
    {
        Poll();
    }
    
    // ボタンクリックイベント
    public void OnClick()
    {
        var bytes = Pack("Hello World!!!!");
        stream.Write(bytes, 0, bytes.Length);
        stream.Flush();
    }
    // Workaround : Jsonなどの形式にシリアライズ。(各自実装)
    byte[] Pack(object obj)
    {
        // object -> byte[]
        return new byte[0];
    }
}