Add ContentLayers widgets from super_editor (Resolves #49)

.github/workflows/pr_validation.yml

@@ -1,7 +1,7 @@
 name: Run analysis and tests for pull requests
 on: [pull_request]
 jobs:
-  test:
+  analysis:
     runs-on: ubuntu-latest
     steps:
       # Checkout the PR branch
@@ -18,6 +18,20 @@ jobs:
       # Static analysis
       - run: flutter analyze
 
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      # Checkout the PR branch
+      - uses: actions/checkout@v3
+
+      # Setup Flutter environment
+      - uses: subosito/flutter-action@v2
+        with:
+          channel: "stable"
+
+      # Download all the packages that the app uses
+      - run: flutter pub get
+
       # Run all tests
       - run: flutter test
 
@@ -36,8 +50,5 @@ jobs:
       # Download all the packages that the app uses
       - run: flutter pub get
 
-      # Static analysis
-      - run: flutter analyze
-
       # Run all tests
       - run: flutter test test_goldens

lib/follow_the_leader.dart

@@ -1,8 +1,11 @@
 library follow_the_leader;
 
 export 'src/build_in_order.dart';
+export 'src/content_layers.dart';
 export 'src/follower.dart';
 export 'src/follower_extensions.dart';
 export 'src/leader_link.dart';
 export 'src/leader.dart';
 export 'src/logging.dart';
+export 'src/render_sliver_ext.dart';
+export 'src/sliver_hybrid_stack.dart';