anchor.diff:      } else if (url.hasQuery && url.queryParameters['source'] != null) {
         Future<UuidContainer> futureGistId = dartSupportServices
             .retrieveGist(id: url.queryParameters['source']);
  -      await futureGistId.then((UuidContainer gistId) {
  +      futureGistId.then((UuidContainer gistId) {
           gistLoader.loadGist(gistId.uuid).then((Gist backing) {
             editableGist.setBackingGist(backing);
             router.go('gist', {'gist': backing.id});
  
positive.code:         ..uuid = url.queryParameters['export'];
        Future<PadSaveObject> exportPad =
            dartSupportServices.pullExportContent(requestId);
        await exportPad.then((pad) {
          Gist blankGist = createSampleGist();
          blankGist.getFile('main.dart').content = pad.dart;
          blankGist.getFile('index.html').content = pad.html;
  
negative.code:     }
    }
  
    Stream get onChanged => file.onChanged.map((value) => value);
  }
  
  class EditorDocumentProperty implements Property {
  