specify when a Future completes for IOSink's addStream

sdk/lib/io/io_sink.dart

Index: sdk/lib/io/io_sink.dart
diff --git a/sdk/lib/io/io_sink.dart b/sdk/lib/io/io_sink.dart
index 89cd586cafbb14575bdc5b4a19f042526d2886ca..19899dfd4fced7cd8e2979bb67ac5e74582aa7d6 100644
--- a/sdk/lib/io/io_sink.dart
+++ b/sdk/lib/io/io_sink.dart
@@ -96,7 +96,8 @@ abstract class IOSink implements StreamSink<List<int>>, StringSink {
   void addError(error, [StackTrace stackTrace]);
 
   /**
-   * Adds all elements of the given [stream] to `this`.
+   * Returns a [Future] that completes when

[Lasse Reichstein Nielsen, 2015/09/21 09:50:47]

Retain the original first line, then add these two as well (after an empty
line).

We usually have a simple first line that describes what happens.
Then , after an empty line, we describe in more detail what parameters means and
what is returned.
A doc that starts with "Returns ..." is generally reserved for getters (or
functions which should probably have been getters).

[sethladd, 2015/09/21 09:56:21]

Done.

+   * all elements of the given [stream] are added to `this`.
    */
   Future addStream(Stream<List<int>> stream);