unembed() actually exists in the Flash object, it will internally disconnect the Flash SWF from the server. However, it didn't remove the SWF object itself from the DOM.
That's been fixed now and I added the line you suggested to the client.
You can use
to disconnect the client from the server (regardless of transport method of course).
It's live now on the same URL, try it out and let me know if it doesn't work.