public EventFeedObserver(Uri uri, ISyndicationFormatter atomFormatter, IFeedChainFactory feedChainFactory, ISubscriptionPersistance persistance)
        {
            _uri = uri;
            _atomFormatter = atomFormatter;
            _feedChainFactory = feedChainFactory;
            _persistance = persistance;

            _subscriptionId = _persistance.Register(uri.ToString());
            LastObservedEventId = _persistance.GetLastObservedEventId(_subscriptionId);
        }
 public IEnumerable<FeedData> Get(string startUrl, ISyndicationFormatter syndicationFormatter)
 {
     return new FeedChain(startUrl, syndicationFormatter);
 }