chore: init from code-review-graph-main snapshot (v2.3.7)

tests/fixtures/sample.dart

@@ -0,0 +1,42 @@
+import 'dart:async';
+import 'package:flutter/material.dart';
+
+abstract class Animal {
+  String get name;
+  void speak();
+}
+
+mixin SwimmingMixin {
+  void swim() => print('swimming');
+}
+
+enum PetType { dog, cat, bird }
+
+class Dog extends Animal with SwimmingMixin {
+  final String name;
+  final PetType type;
+
+  Dog(this.name) : type = PetType.dog;
+
+  @override
+  void speak() {
+    print('Woof! I am $name');
+  }
+
+  Future<void> fetch(String item) async {
+    await _run();
+    print('Fetched $item');
+  }
+
+  void _run() {
+    print('running');
+  }
+
+  static Dog create(String name) {
+    return Dog(name);
+  }
+}
+
+Dog createDog(String name) {
+  return Dog(name);
+}