start method
Implementation
Future<void> start() async {
final handler = shelf.Cascade()
.add(stat.createStaticHandler(rootDirectory,
defaultDocument: 'index.html',
listDirectories: true,
))
.handler;
final server = await io.serve(handler, 'localhost', 8080);
print('Serving at http://${server.address.host}:${server.port}');
}