start method
Binds the loopback server and returns the redirect URI.
Implementation
Future<String> start({Duration timeout = const Duration(minutes: 5)}) async {
await close();
_result = Completer<AiinCallback?>();
_server = await HttpServer.bind(InternetAddress.loopbackIPv4, 0);
_timer = Timer(timeout, () => _complete(null));
_server!.listen(_handle, onDone: () => _complete(null));
return callbackUrl!;
}