Add type info to fix analyzer failures for 1.23.0-dev.5.0

lib/src/util/stream_queue.dart

Index: lib/src/util/stream_queue.dart
diff --git a/lib/src/util/stream_queue.dart b/lib/src/util/stream_queue.dart
index 1c2e3b2252ac854e65a0376343c1c5101af94e8a..c37c2ca05d8072d780ae917ce0c70c9bfa930f6a 100644
--- a/lib/src/util/stream_queue.dart
+++ b/lib/src/util/stream_queue.dart
@@ -488,7 +488,7 @@ class _TakeRequest<T> implements _EventRequest {
   final _completer = new Completer<List<T>>();
 
   /// List collecting events until enough have been seen.
-  final List _list = <T>[];
+  final _list = <T>[];
 
   /// Number of events to capture.
   ///