chore(aws_common): Crypto-secure UUID (#1573)

Author: dnys1

packages/aws_common/lib/aws_common.dart

@@ -34,3 +34,4 @@ export 'src/util/equatable.dart';
 export 'src/util/json.dart';
 export 'src/util/print.dart';
 export 'src/util/serializable.dart';
+export 'src/util/uuid.dart';

packages/aws_common/lib/src/util/uuid.dart

@@ -0,0 +1,25 @@
+// Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'package:uuid/uuid.dart';
+import 'package:uuid/uuid_util.dart';
+
+/// Generates a crypto-secure UUID (v4).
+String uuid() => const Uuid().v4(
+      // Use the crypto-secure RNG per `package:uuid` docs:
+      // https://github.com/Daegalus/dart-uuid/blob/d7bc930942afc752edd0fd15f8bf8234d81dfeda/example/example.dart#L21
+      options: const <String, Object>{
+        'rng': UuidUtil.cryptoRNG,
+      },
+    );

packages/aws_common/pubspec.yaml

@@ -12,6 +12,7 @@ dependencies:
   collection: ^1.15.0
   http: ^0.13.4
   meta: ^1.7.0
+  uuid: 3.0.6
 
 dev_dependencies:
   amplify_lints: ^1.0.0