Сокеты. Отправка сообщений всем клиентам или только одному - C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Threading;

namespace ConsoleServer
{
    public struct client_attr
    {
        public int count;
        public string ip;
        public string name;
    }
    public struct connections
    {
        public string firstClient;
        public string secondClient;
        public string[] msg;
    }
    class Program
    {
        public static string data = null;
        public static bool exit = false;
        static int count = 0;
        static bool spisok = false;
        static string[] clients = new string[10];
        static String host = System.Net.Dns.GetHostName();

        public static void start_server()
        {
            try
            {
                System.Net.IPAddress ip = System.Net.Dns.GetHostByName(host).AddressList[0];
                IPAddress localAddress = IPAddress.Parse(ip.ToString());
 
                IPEndPoint ipEndpoint = new IPEndPoint(localAddress, 65);
 
                Socket sListener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
 
                sListener.Bind(ipEndpoint);
                sListener.Listen(1);
 
                while (true)
                {
                    //Invoke(new AddMessageDelegate(LogAdd), new object[] { "Ожидаем соединение. " + ip.ToString() + ":65" + "\n" });
                    Console.WriteLine("Ожидаем соединение. " + ip.ToString() + ":65");
 
                    Socket handler = sListener.Accept();
 
                    Thread Thread2 = new Thread(delegate() { obs(handler); });
                    Thread2.Start();
                    if (exit == true)
                    {
                        handler.Shutdown(SocketShutdown.Both);
                        handler.Close();
                        Thread2.Abort();
                        break;
                    }
                }
 
            }
            catch (Exception ex)
            {
               // Invoke(new AddMessageDelegate(LogAdd), new object[] { ex.ToString() + "\n" });
                Console.WriteLine(ex.ToString());
            }
        }
        static void reciv(Socket handler)
        {
            try
            {
                byte[] bytes = new byte[1024];
                int bytesRec = handler.Receive(bytes);
                data = Encoding.UTF8.GetString(bytes, 0, bytesRec);
            }
            catch
            {
                // Invoke(new AddMessageDelegate(LogAdd), new object[] { "Соединение прервано" });
                Console.WriteLine("Соединение прервано");
            }
        }
        static void obs(Socket handler)
        {
            client_attr[] client1 = new client_attr[30];
            
            count += 1;
            clients[count] = ((IPEndPoint)handler.RemoteEndPoint).Address.ToString();
            while (true)
            {
                Thread thread3 = new Thread(delegate() { reciv(handler); });
                thread3.Start();
 
                //Invoke(new AddMessageDelegate(LogAdd), new object[] { count + "\n" });
                //Invoke(new AddMessageDelegate(LogAdd), new object[] { data + "\n" });
                //Console.WriteLine(count);
               // Console.WriteLine(data);
                    if (data == "exit")
                    {
 
                        //Invoke(new Action(() => { listBox1.Items.RemoveAt(client1[count].count); }));
                        client1[count].count = -1;
                        client1[count].ip = null;
                        client1[count].name = null;
                        handler.Shutdown(SocketShutdown.Both);
                        handler.Close();
                       // Invoke(new AddMessageDelegate(LogAdd), new object[] { "Соединение завершено\n" });
                        Console.WriteLine("Соединение завершено");
                        Console.WriteLine("disconnect" + ":" + client1[count].name + "::" + count);
                        break;
                    }
                    else if (client1[count].name == null)
                    {
                        client1[count].ip = ((IPEndPoint)handler.RemoteEndPoint).Address.ToString();
                        client1[count].name = data;
                        client1[count].count = count;
                        //byte [] list_mem = new byte[listBox1.Items.Count];
                        handler.Send(Encoding.UTF8.GetBytes(client1[count].name+""));
 
                        // handler.Send(Encoding.UTF8.GetBytes();
 
                       // Invoke(new Action(() => { listBox1.Items.Add(client1[count].name); }));
                       // Invoke(new AddMessageDelegate(LogAdd), new object[] { "Клиент " + client1[count].name + " с IP: " + client1[count].ip + " подключился.\n" });
                        Console.WriteLine("Клиент " + client1[count].name + " с IP: " + client1[count].ip + " подключился.");
                        
                    }
                    else if (client1[count].name != null)
                    {
                        for (int i = 1; i < count+1; i++)
                        {
                        // if (client1[0].name != client1[count].name)
                        // {
                            if (spisok == false)
                            {
                                handler.Send(Encoding.UTF8.GetBytes(i+":"+client1[i].name));
                                spisok = true;
                                // Invoke(new AddMessageDelegate(LogAdd), new object[] { client1[count].name });
                                //Console.WriteLine(client1[count].name);
                                // }
                            }
                        }
                       
                    }
                    else if (data.IndexOf("connect") >= 0)
                    {
                        connections[] connect = new connections[1];
                        int start = data.IndexOf(":");
                        int end = data.IndexOf("::");
                        int len = end - start;
                        connect[0].firstClient = data.Substring(start, len);
                        start = data.IndexOf("::");
                        end = data.IndexOf(":::");
                        len = end - start;
                        connect[0].secondClient = data.Substring(start, len);
                       // Invoke(new AddMessageDelegate(LogAdd), new object[] { connect[0].firstClient + "" + connect[0].secondClient });
                        Console.WriteLine(connect[0].firstClient + "" + connect[0].secondClient);
                    }
       
                Thread.Sleep(500);
            }
        }
        static void Main(string[] args)
        {
            start_server();
        }