C# Pub/Sub example

public class PubSub
{
    readonly Queue<string> queue = new Queue<string>();

    object locker = new object();

    public string Subscribe()
    {
        string text;
        lock (locker)
        {
            while(queue.Count== 0)
            {
                Monitor.Wait(locker);                    
            }
            text = queue.Dequeue();
        }
        return text;
    }

    public void Publish(string request)
    {
        lock (locker)
        {
            queue.Enqueue(request);
            Monitor.PulseAll(locker);
        }
    }
}

class Program
{
    Random r = new Random();

    public Program()
    {
        PubSub pubSub = new PubSub();

        Thread t1 = new Thread(delegate() { Publish(pubSub); });
        Thread t2 = new Thread(delegate() { Subscribe(pubSub); });

        t1.Start();
        t2.Start();

        t1.Join();
        t2.Join();

        Console.WriteLine("Completed.");

        Console.ReadLine();
    }

    void Publish(PubSub pubSub)
    {
        for (int i = 1; i <= 10; i++)
        {                
            Thread.Sleep(r.Next(10, 100));
            pubSub.Publish(string.Format("Publishing {0}",i));
        }
        pubSub.Publish(null);
    }

    void Subscribe(PubSub pubSub)
    {
        while(true)
        {
            string text = pubSub.Subscribe();
            if(text==null) return;
            Console.WriteLine(text);
        }
    }

    static void Main(string[] args)
    {
        new Program();
    }
}