gistfile1.cs

public class Connection
{
    Socket connection;
    IPublisher publisher;
    
    public Connection(IPublisher publisher, Socket connection)
    {
      this.publisher = publisher;
      this.connection = connection;
    }
    
    void Listen()
    {
      while(connection.IsConnected)
      {
        var buffer = connection.Receive();
        var data = buffer.ConvertToData(); //extension
        this.publisher.Publish(new WorldTimeChanged(data));
      }
    }
{

public class Publisher : IPublisher
{
    private readonly ConcurrentDictionary<Type, List<ISubscription>> listeners =
        new ConcurrentDictionary<Type, List<ISubscription>>();
        
    ISubscription Subscribe<TMessageType>(Action<TMessageType, ISubscription> callback, Func<TMessageType, bool> condition = null)
    {
      this.listeners.TryAdd(typeof(TMessageType), new List<ISubscription>());
      List<ISubscription> subscribers = listeners[messageType];

      var handler = new Notification<TMessageType>();
      handler.Register(callback, condition);
      subscribers.Add(handler);
    }
    
    void Publish<T>(T message)
    {
      var listenersToPublishTo = this.listeners[typeof(T)].OfType<Notification<T>>().ToArray();
      foreach (Notification<T> handler in listenersToPublishTo)
      {
          handler.ProcessMessage(message);
      }
    }
}

public class World
{
  IPublisher publisher;
  public World(IPublisher publisher) => this.publisher = publisher;
  
  public double WorldTime {get; private set;} 
  
  // Initialized on the main thread
  void Initialize()
  {
    publisher.Subscribe<WorldTimeChanged>((message, sub) => this.WorldTime = message.NewTime);
  }
}