Opt-out examples/
diff --git a/example/DeltaBlue.dart b/example/DeltaBlue.dart
index c676748..02fb696 100644
--- a/example/DeltaBlue.dart
+++ b/example/DeltaBlue.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// Copyright 2011 Google Inc. All Rights Reserved.
// Copyright 1996 John Maloney and Mario Wolczko
//
diff --git a/example/FluidMotion/dart/FluidMotion.dart b/example/FluidMotion/dart/FluidMotion.dart
index 1031b42..e580713 100644
--- a/example/FluidMotion/dart/FluidMotion.dart
+++ b/example/FluidMotion/dart/FluidMotion.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
import 'dart:html';
/// Copyright 2013 the V8 project authors. All rights reserved.
diff --git a/example/Richards.dart b/example/Richards.dart
index 79487a6..247709a 100644
--- a/example/Richards.dart
+++ b/example/Richards.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
diff --git a/example/Template.dart b/example/Template.dart
index 3f569b4..879732d 100644
--- a/example/Template.dart
+++ b/example/Template.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// Copyright 2012 Google Inc. All Rights Reserved.
// Import BenchmarkBase class.
diff --git a/example/Tracer/dart/Tracer.dart b/example/Tracer/dart/Tracer.dart
index fa4a308..d3c02b2 100644
--- a/example/Tracer/dart/Tracer.dart
+++ b/example/Tracer/dart/Tracer.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// The ray tracer code in this file is written by Adam Burmister. It
// is available in its original form from:
//
diff --git a/example/Tracer/dart/app.dart b/example/Tracer/dart/app.dart
index 08d5ca3..7c6c359 100644
--- a/example/Tracer/dart/app.dart
+++ b/example/Tracer/dart/app.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
library ray_trace;
import 'dart:html';
diff --git a/example/Tracer/dart/color.dart b/example/Tracer/dart/color.dart
index ecf8e10..5892ce8 100644
--- a/example/Tracer/dart/color.dart
+++ b/example/Tracer/dart/color.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// The ray tracer code in this file is written by Adam Burmister. It
// is available in its original form from:
//
diff --git a/example/Tracer/dart/engine.dart b/example/Tracer/dart/engine.dart
index 5d710e8..03aaacb 100644
--- a/example/Tracer/dart/engine.dart
+++ b/example/Tracer/dart/engine.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// The ray tracer code in this file is written by Adam Burmister. It
// is available in its original form from:
//
diff --git a/example/Tracer/dart/materials.dart b/example/Tracer/dart/materials.dart
index e12aeb3..de2e0dc 100644
--- a/example/Tracer/dart/materials.dart
+++ b/example/Tracer/dart/materials.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// The ray tracer code in this file is written by Adam Burmister. It
// is available in its original form from:
//
diff --git a/example/Tracer/dart/renderscene.dart b/example/Tracer/dart/renderscene.dart
index 5e87f41..4a25738 100644
--- a/example/Tracer/dart/renderscene.dart
+++ b/example/Tracer/dart/renderscene.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// The ray tracer code in this file is written by Adam Burmister. It
// is available in its original form from:
//
diff --git a/example/Tracer/dart/scene.dart b/example/Tracer/dart/scene.dart
index 3de2f09..9465ac9 100644
--- a/example/Tracer/dart/scene.dart
+++ b/example/Tracer/dart/scene.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// The ray tracer code in this file is written by Adam Burmister. It
// is available in its original form from:
//
diff --git a/example/Tracer/dart/shapes.dart b/example/Tracer/dart/shapes.dart
index 6fb33d4..c7d1ff6 100644
--- a/example/Tracer/dart/shapes.dart
+++ b/example/Tracer/dart/shapes.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// The ray tracer code in this file is written by Adam Burmister. It
// is available in its original form from:
//
diff --git a/example/Tracer/dart/vector.dart b/example/Tracer/dart/vector.dart
index 1694922..d8d7ad6 100644
--- a/example/Tracer/dart/vector.dart
+++ b/example/Tracer/dart/vector.dart
@@ -1,3 +1,4 @@
+// @dart=2.8
// The ray tracer code in this file is written by Adam Burmister. It
// is available in its original form from:
//
