Stop using [wrapAsync] in the [prints] matcher.

lib/src/prints_matcher.dart

 // Copyright (c) 2014, 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.
 
 library unittest.prints_matcher;
 
 import 'dart:async';
 
-import 'package:matcher/matcher.dart' hide completes, wrapAsync, expect;
+import 'package:matcher/matcher.dart' hide completes, expect;
 
 import '../unittest.dart';
 
 /// Matches a [Function] that prints text that matches [matcher].
 ///
 /// [matcher] may be a String or a [Matcher].
 ///
 /// If the function this runs against returns a [Future], all text printed by
 /// the function (using [Zone] scoping) until that Future completes is matched.
 ///
@@ skipping 13 matching lines @@
         zoneSpecification: new ZoneSpecification(print: (_, __, ____, line) {
       buffer.writeln(line);
     }));
 
     if (result is! Future) {
       var actual = buffer.toString();
       matchState['prints.actual'] = actual;
       return _matcher.matches(actual, matchState);
     }
 
-    return completes.matches(result.then(wrapAsync((_) {
+    return completes.matches(result.then((_) {
       expect(buffer.toString(), _matcher);
-    }, 'prints')), matchState);
+    }), matchState);
   }
 
   Description describe(Description description) =>
       description.add('prints ').addDescriptionOf(_matcher);
 
   Description describeMismatch(
       item, Description description, Map matchState, bool verbose) {
     var actual = matchState.remove('prints.actual');
     if (actual == null) return description;
     if (actual.isEmpty) return description.add("printed nothing.");
 
     description.add('printed ').addDescriptionOf(actual);
 
     // Create a new description for the matcher because at least
     // [_StringEqualsMatcher] replaces the previous contents of the description.
     var innerMismatch = _matcher
         .describeMismatch(actual, new StringDescription(), matchState, verbose)
         .toString();
 
     if (innerMismatch.isNotEmpty) {
       description.add('\n   Which: ').add(innerMismatch.toString());
     }
 
     return description;
   }
 }