Remove .writeStream, .consume and rewrite IOSink to correctly implement a (sane) well-defined behav…

tests/standalone/io/stdout_stderr_test.dart

Index: tests/standalone/io/stdout_stderr_test.dart
diff --git a/tests/standalone/io/stdout_stderr_test.dart b/tests/standalone/io/stdout_stderr_test.dart
index 4775891cc5ec32ab92472abbd82de4501404af90..ccd1550435184701174bd57c829220f6dd7eb6b2 100644
--- a/tests/standalone/io/stdout_stderr_test.dart
+++ b/tests/standalone/io/stdout_stderr_test.dart
@@ -17,16 +17,18 @@ callIOSink(IOSink sink) {
   sink.add([101, 108, 108, 111, 10]);
 
   var controller = new StreamController();
-  sink.writeStream(controller.stream);
+  var future = sink.addStream(controller.stream);
   controller.add([72, 101, 108]);
   controller.add([108, 111, 10]);
   controller.close();
 
-  controller = new StreamController();
-  controller.stream.pipe(sink);
-  controller.add([72, 101, 108]);
-  controller.add([108, 111, 10]);
-  controller.close();
+  future.then((_) {
+    controller = new StreamController();
+    controller.stream.pipe(sink);
+    controller.add([72, 101, 108]);
+    controller.add([108, 111, 10]);
+    controller.close();
+  });
 }
 
 main() {