future_list.dart

@override
Widget build(BuildContext context) {
  return new FutureBuilder<Repositories>(
    future: apiClient.getUserRepositoriesFuture(username),
    builder: (BuildContext context, 
        AsyncSnapshot<Repositories> snapshot) {
      if (snapshot.hasError)
        return new Center(child: new Text("Network error"));
      if (!snapshot.hasData)
        return new Center(
          child: new CircularProgressIndicator(),
        );
      return new ListView.builder(
        itemCount: snapshot.data.nodes.length,
        itemBuilder: (BuildContext context, int index) =>
            new RepoPreviewTile(
              repository: snapshot.data.nodes[index],
            ),
      );
    },
  );
}