Session.cs

// ユーザのセッション情報
// TcpListenerにアクセス要求が来たときに作成されます
using System;
using System.Net.Sockets;

public class Session
{
    TcpClient client;
    NetworkStream stream;                
    Action<Session, Command> commandExec;

    public Session(TcpClient client, Action<Session, Command> commandExec)
    {
        this.client = client;
        this.stream = client.GetStream();
        this.commandExec = commandExec;
    }
    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;
    }
    
    public void Send(byte[] bytes)
    {
        stream.Write(bytes, 0, bytes.Length);
        stream.Flush();
    }
}