Modernize the package's style.

lib/src/result/capture_sink.dart

Index: lib/src/result/capture_sink.dart
diff --git a/lib/src/result/capture_sink.dart b/lib/src/result/capture_sink.dart
new file mode 100644
index 0000000000000000000000000000000000000000..74745251dc86c90662d3b71a72429e8694771ad0
--- /dev/null
+++ b/lib/src/result/capture_sink.dart
@@ -0,0 +1,27 @@
+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:async';
+
+import '../result.dart';
+
+/// Use [Result.captureSinkTransformer].
+@Deprecated("Will be removed in async 2.0.0.")
+class CaptureSink<T> implements EventSink<T> {
+  final EventSink _sink;
+
+  CaptureSink(EventSink<Result<T>> sink) : _sink = sink;
+
+  void add(T value) {
+    _sink.add(new Result.value(value));
+  }
+
+  void addError(Object error, [StackTrace stackTrace]) {
+    _sink.add(new Result.error(error, stackTrace));
+  }
+
+  void close() {
+    _sink.close();
+  }
+}