Simple pub sub pattern demo

Program.cs

using System;
using System.Collections.Generic;
using System.Threading;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            MessageManager mm = new MessageManager();
            mm.OnMessageReceived += mm_OnMessageReceived;
            mm.Begin();

            Console.WriteLine("Client started");
            Console.ReadKey();
        }

        static void mm_OnMessageReceived(Message msg)
        {
            Console.WriteLine("You have new message from publisher. Id:" + msg.Id + ", Text:" + msg.Text);
        }
    }

    public class MessageManager
    {
        public delegate void OnMessageReceivedDelegate(Message Message);
        public event OnMessageReceivedDelegate OnMessageReceived;

        private DemoService _service;
        private IEnumerable<Message> _messages;

        public MessageManager()
        {
        }

        public void Begin()
        {
            while (true)
            {
                HandleNewMessage();
            }
        }

        private void HandleNewMessage()
        {
            Console.WriteLine("New connection is opening");

            _service = new DemoService();
            _messages = _service.GetAll();

            var enumerator = _messages.GetEnumerator();
            while (enumerator.MoveNext())
            {
                if (OnMessageReceived != null)
                {
                    OnMessageReceived(enumerator.Current);
                }

            }

            Console.WriteLine("Connection is closed");
        }
    }

    public class Message
    {
        public int Id { get; set; }

        public string Text { get; set; }
    }

    public class DemoService
    {
        public IEnumerable<Message> GetAll()
        {
            for (int i = 0; i < 20; i++)
            {
                Thread.Sleep(new Random().Next(10, 300));
                yield return new Message() { Id = i, Text = "Message " + i + " is published" };
            }

            yield break;
        }
    }
}