Modernize the package's style.

test/result_test.dart

 // Copyright (c) 2013, 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 "dart:collection";
 
-import "package:async/result.dart";
+import "package:async/async.dart";
 import "package:stack_trace/stack_trace.dart";
 import "package:test/test.dart";
 
 void main() {
   var stack = new Trace.current();
 
   test("create result value", () {
     Result<int> result = new Result<int>.value(42);
     expect(result.isValue, isTrue);
     expect(result.isError, isFalse);
@@ skipping 311 matching lines @@
   void add(T value) { onData(value); }
   void addError(error, [StackTrace stack]) { onError(error, stack); }
   void close() { onDone(); }
 
   static void _nullData(value) { fail("Unexpected sink add: $value"); }
   static void _nullError(e, StackTrace s) {
     fail("Unexpected sink addError: $e");
   }
   static void _nullDone() { fail("Unepxected sink close"); }
 }