[pigeon] feat(pigeon): expose SwiftOptions (#2271)

diff --git a/packages/pigeon/CHANGELOG.md b/packages/pigeon/CHANGELOG.md
index 03c36a6..c084207 100644
--- a/packages/pigeon/CHANGELOG.md
+++ b/packages/pigeon/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.0.1
+
+* Exposes `SwiftOptions`.
+
 ## 4.0.0
 
 * [java] **BREAKING CHANGE**: Changes style for enum values from camelCase to snake_case.
diff --git a/packages/pigeon/lib/generator_tools.dart b/packages/pigeon/lib/generator_tools.dart
index bd898ce..6a32c2c 100644
--- a/packages/pigeon/lib/generator_tools.dart
+++ b/packages/pigeon/lib/generator_tools.dart
@@ -9,7 +9,7 @@
 import 'ast.dart';
 
 /// The current version of pigeon. This must match the version in pubspec.yaml.
-const String pigeonVersion = '4.0.0';
+const String pigeonVersion = '4.0.1';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
diff --git a/packages/pigeon/lib/pigeon.dart b/packages/pigeon/lib/pigeon.dart
index 7a26cf3..737954b 100644
--- a/packages/pigeon/lib/pigeon.dart
+++ b/packages/pigeon/lib/pigeon.dart
@@ -9,3 +9,4 @@
 export 'java_generator.dart' show JavaOptions;
 export 'objc_generator.dart' show ObjcOptions;
 export 'pigeon_lib.dart';
+export 'swift_generator.dart' show SwiftOptions;
diff --git a/packages/pigeon/pubspec.yaml b/packages/pigeon/pubspec.yaml
index 12914bc..c453ffb 100644
--- a/packages/pigeon/pubspec.yaml
+++ b/packages/pigeon/pubspec.yaml
@@ -2,7 +2,7 @@
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3Apigeon
-version: 4.0.0 # This must match the version in lib/generator_tools.dart
+version: 4.0.1 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
diff --git a/packages/pigeon/test/pigeon_test.dart b/packages/pigeon/test/pigeon_test.dart
new file mode 100644
index 0000000..7982681
--- /dev/null
+++ b/packages/pigeon/test/pigeon_test.dart
@@ -0,0 +1,23 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:pigeon/pigeon.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('Should be able to import JavaOptions', () async {
+    const JavaOptions javaOptions = JavaOptions();
+    expect(javaOptions, isNotNull);
+  });
+
+  test('Should be able to import ObjcOptions', () async {
+    const ObjcOptions objcOptions = ObjcOptions();
+    expect(objcOptions, isNotNull);
+  });
+
+  test('Should be able to import SwiftOptions', () async {
+    const SwiftOptions swiftOptions = SwiftOptions();
+    expect(swiftOptions, isNotNull);
+  });
+}