Rename unsubscribe to cancel.

sdk/lib/io/http_impl.dart

Index: sdk/lib/io/http_impl.dart
diff --git a/sdk/lib/io/http_impl.dart b/sdk/lib/io/http_impl.dart
index 37437c041b2e989224f5162818cefd114baefe93..b3eb83ca3eebf14184dea30f14c85028c01dffb4 100644
--- a/sdk/lib/io/http_impl.dart
+++ b/sdk/lib/io/http_impl.dart
@@ -241,14 +241,14 @@ class _StreamingHttpRequestResponseBase extends _HttpRequestResponseBase {
   _StreamingHttpRequestResponseBase(_HttpConnectionBase connection)
     : super(connection);
 
-  StreamSubscription<T> subscribe({void onData(T event),
-                                   void onError(AsyncError error),
-                                   void onDone(),
-                                   bool unsubscribeOnError}) {
-    return _controller.stream.subscribe(onData: onData,
-                                        onError: onError,
-                                        onDone: onDone,
-                                        unsubscribeOnError: unsubscribeOnError);
+  StreamSubscription<T> listen(void onData(T event),
+                               { void onError(AsyncError error),
+                                 void onDone(),
+                                 bool unsubscribeOnError}) {
+    return _controller.stream.listen(onData,
+                                     onError: onError,
+                                     onDone: onDone,
+                                     unsubscribeOnError: unsubscribeOnError);
   }
 
   Stream transform({void onData(T data, StreamSink sink),