Migrated test block 171 to Dart 2.0.

tests/lib_2/async/slow_consumer3_test.dart

Index: tests/lib_2/async/slow_consumer3_test.dart
diff --git a/tests/lib/async/slow_consumer3_test.dart b/tests/lib_2/async/slow_consumer3_test.dart
similarity index 94%
rename from tests/lib/async/slow_consumer3_test.dart
rename to tests/lib_2/async/slow_consumer3_test.dart
index 96ff202fbdd01870504d7e4f03c89e146d40beac..ae83f204e5414a6880ab9e87361b9b33a062bce8 100644
--- a/tests/lib/async/slow_consumer3_test.dart
+++ b/tests/lib_2/async/slow_consumer3_test.dart
@@ -14,11 +14,11 @@ const int KB = 1024;
 const int MB = KB * KB;
 const int GB = KB * KB * KB;
 
-class SlowConsumer extends StreamConsumer {
+class SlowConsumer extends StreamConsumer<List<int>> {
   int receivedCount = 0;
   final int bytesPerSecond;
   final int bufferSize;
-  final List bufferedData = [];
+  final List<int> bufferedData = [];
   int usedBufferSize = 0;
   int finalCount;
 
@@ -60,7 +60,7 @@ class SlowConsumer extends StreamConsumer {
   }
 }
 
-Stream<List> dataGenerator(int bytesTotal, int chunkSize) {
+Stream<List<int>> dataGenerator(int bytesTotal, int chunkSize) {
   int chunks = bytesTotal ~/ chunkSize;
   return new Stream.fromIterable(new Iterable.generate(chunks, (_) {
     // This assumes one byte per entry. In practice it will be more.