dart 2.9

packages/in_app_purchase/example/test_driver/test/integration_test.dart

@@ -2,6 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';