`wssv.Stop()` Never Stops

Per README for server code:

using System;
using WebSocketSharp;
using WebSocketSharp.Server;

namespace Example
{
  public class Laputa : WebSocketBehavior
  {
    protected override void OnMessage (MessageEventArgs e)
    {
      var msg = e.Data == "BALUS"
                ? "Are you kidding?"
                : "I'm not available now.";

      Send (msg);
    }
  }

  public class Program
  {
    public static void Main (string[] args)
    {
      var wssv = new WebSocketServer ("ws://dragonsnest.far");

      wssv.AddWebSocketService<Laputa> ("/Laputa");
      wssv.Start ();
      Console.ReadKey (true);
      wssv.Stop ();
    }
  }
}

If you actually run it, the server never stops after the last call.

Start with the server example in README and trace the behavior of WebSocketServer.Stop() after the Console.ReadKey call. Reproduce the example and inspect the stop path; done means the server process terminates after wssv.Stop() returns.