gistfile1.cs

const string socketAddr = "tcp://localhost:30101";
public IObservable<bool> ConnectOrBecomeAnnounceServer()
{
    if (_socket != null)
    {
	return Observable.Throw<bool>(new Exception("Already connected"));
    }

    return ConnectToAnnounceServer()
	.Catch(BecomeAnnounceServer())
	.SelectMany(sockAndCtx =>
    {
	if (sockAndCtx == null)
	{
	    return Observable.Throw<bool>(new Exception("Can't connect nor become announce server"));
	}

	_socket = _host.RegisterSocket(sockAndCtx.Item1);
	_isAnnounceServer = sockAndCtx.Item2;
	return Observable.Return(_isAnnounceServer);
    });
}