anchor.diff:  
     _FirebaseSubscription(Firebase ref) {
       _current = new DataSnapshot._(ref, null);
  -    _source = new _EventSource(ref.url.toString());
  +    _source = new _EventSource(ref.url.toString(), auth: ref._auth);
   
       StreamSubscription subscription;
   
  
positive.code: 
  class _EventSource {
    final Uri url;
  
    http.StreamedResponse _response;
    http.Client _client;
  
    StreamController<_Event> _controller;
  
    _EventSource(String url, {bool withCredentials: false})
        : this.url = Uri.parse(url) {
  
      _controller = new StreamController(
  
negative.code:   }
  
    Future _open() async {
      var request = new http.Request("GET", url.resolve(".json")
          .replace(queryParameters: auth!=null ? {"auth": auth} : const {}));
      request.headers["Accept"] = "text/event-stream";
      _client = new http.Client();
  
  