connect method Null safety

Implementation

static Future<FlutterWebConnection> connect(
    String url,
    Map<String, dynamic> settings,
    {Duration? timeout}) async {
  final String sessionId = settings['session-id'].toString();
  final Uri sessionUri = Uri.parse(settings['session-uri'].toString());
  final async_io.WebDriver driver = async_io.WebDriver(
      sessionUri,
      sessionId,
      json.decode(settings['session-capabilities'] as String) as Map<String, dynamic>,
      async_io.AsyncIoRequestClient(sessionUri.resolve('session/$sessionId/')),
      _convertToSpec(settings['session-spec'].toString().toLowerCase()));
  if (settings['android-chrome-on-emulator'] == true) {
    final Uri localUri = Uri.parse(url);
    // Converts to Android Emulator Uri.
    // Hardcode the host to 10.0.2.2 based on
    // https://developer.android.com/studio/run/emulator-networking
    url = Uri(scheme: localUri.scheme, host: '10.0.2.2', port:localUri.port).toString();
  }
  await driver.get(url);

  await waitUntilExtensionInstalled(driver, timeout);
  return FlutterWebConnection(driver, settings['support-timeline-action'] as bool);
}