Update charted to 0.4.8 and roll

packages/quiver/lib/async.dart

 // Copyright 2013 Google Inc. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 library quiver.async;
 
 import 'dart:async';
 
+import 'package:quiver/iterables.dart' show IndexedValue;
 import 'package:quiver/time.dart';
 
+part 'src/async/collect.dart';
 part 'src/async/countdown_timer.dart';
+part 'src/async/concat.dart';
+part 'src/async/enumerate.dart';
 part 'src/async/future_group.dart';
 part 'src/async/future_stream.dart';
 part 'src/async/iteration.dart';
 part 'src/async/metronome.dart';
+part 'src/async/stream_buffer.dart';
 part 'src/async/stream_router.dart';
 
-/**
- * The signature of a one-shot [Timer] factory.
- */
+/// The signature of a one-shot [Timer] factory.
 typedef Timer CreateTimer(Duration duration, void callback());
 
-/**
- * Creates a new one-shot [Timer] using `new Timer(duration, callback)`.
- */
+/// Creates a new one-shot [Timer] using `new Timer(duration, callback)`.
 Timer createTimer(Duration duration, void callback()) =>
     new Timer(duration, callback);
-/**
- * The signature of a periodic timer factory.
- */
+
+/// The signature of a periodic timer factory.
 typedef Timer CreateTimerPeriodic(Duration duration, void callback(Timer));
 
-/**
- * Creates a new periodic [Timer] using
- * `new Timer.periodic(duration, callback)`.
- */
-Timer createTimerPeriodic(Duration duration, void callback(Timer)) =>
+/// Creates a new periodic [Timer] using
+/// `new Timer.periodic(duration, callback)`.
+Timer createTimerPeriodic(Duration duration, void callback(Timer t)) =>
     new Timer.periodic(duration, callback);