Synchronized publisher in C#

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

using ZeroMQ;

namespace Examples
{
static partial class Program
{
const int SyncPub_SubscribersExpected = 3; // We wait for 3 subscribers

public static void SyncPub(string[] args)
{
//
// Synchronized publisher
//
// Author: metadings
//

// Socket to talk to clients and
// Socket to receive signals
using (var context = new ZContext())
using (var publisher = new ZSocket(context, ZSocketType.PUB))
using (var syncservice = new ZSocket(context, ZSocketType.REP))
{
publisher.SendHighWatermark = 1100000;
publisher.Bind("tcp://*:5561");

syncservice.Bind("tcp://*:5562");

// Get synchronization from subscribers
int subscribers = SyncPub_SubscribersExpected;
do
{
Console.WriteLine("Waiting for {0} subscriber" + (subscribers > 1 ? "s" : string.Empty) + "…", subscribers);

// - wait for synchronization request
syncservice.ReceiveFrame();

// - send synchronization reply
syncservice.Send(new ZFrame());
}
while (--subscribers > 0);

// Now broadcast exactly 20 updates followed by END
Console.WriteLine("Broadcasting messages:");
for (int i = 0; i < 20; ++i)
{
Console.WriteLine("Sending {0}…", i);
publisher.Send(new ZFrame(i));
}
publisher.Send(new ZFrame("END"));
}
}
}
}