Add type info to fix analyzer failure, missed this one change in previous cl

lib/src/util/stream_queue.dart

 // Copyright (c) 2015, 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.
 
 // TODO(nweiz): Get rid of this when https://codereview.chromium.org/1241723003/
 // lands.
 import 'dart:async';
 import 'dart:collection';
 
 import "package:async/async.dart" hide ForkableStream, StreamQueue;
@@ skipping 421 matching lines @@
 
   Future<T> get future => _completer.future;
 
   bool addEvents(Queue<Result> events) {
     if (events.isEmpty) return false;
     events.removeFirst().complete(_completer);
     return true;
   }
 
   void close(Queue<Result> events) {
-    var errorFuture =
+    Future<T> errorFuture =
         new Future.sync(() => throw new StateError("No elements"));

[kevmoo, 2017/03/14 19:04:01]

Instead of this, try doing `new Future<T>.sync` – it's cleaner

[keertip, 2017/03/14 19:12:49]

Done.

     _completer.complete(errorFuture);
   }
 }
 
 /// Request for a [StreamQueue.skip] call.
 class _SkipRequest implements _EventRequest {
   /// Completer for the future returned by the skip call.
   final _completer = new Completer<int>();
 
   /// Number of remaining events to skip.
@@ skipping 234 matching lines @@
         event.addTo(controller);
       }
 
       var fork = _streamQueue._sourceStream.fork();
       controller.addStream(fork, cancelOnError: false)
           .whenComplete(controller.close);
       _completer.setSourceStream(controller.stream);
     }
   }
 }