diff --git a/dev/devicelab/lib/tasks/perf_tests.dart b/dev/devicelab/lib/tasks/perf_tests.dart
index 41ac427852..bae1243c90 100644
--- a/dev/devicelab/lib/tasks/perf_tests.dart
+++ b/dev/devicelab/lib/tasks/perf_tests.dart
@@ -122,7 +122,7 @@ TaskFunction createBasicMaterialCompileTest() {
       await flutter('create', options: <String>['--template=app', sampleAppName]);
     });
 
-    if (!(await sampleDir.exists()))
+    if (!sampleDir.existsSync())
       throw 'Failed to create default Flutter app in ${sampleDir.path}';
 
     return CompileTest(sampleDir.path).run();
diff --git a/packages/flutter_test/test/widget_tester_test.dart b/packages/flutter_test/test/widget_tester_test.dart
index 7d8277c7ab..305f6c66ca 100644
--- a/packages/flutter_test/test/widget_tester_test.dart
+++ b/packages/flutter_test/test/widget_tester_test.dart
@@ -467,6 +467,7 @@ void main() {
       final StringBuffer buf = StringBuffer('1');
       await tester.runAsync(() async {
         buf.write('2');
+        //ignore: avoid_slow_async_io
         await Directory.current.stat();
         buf.write('3');
       });