Adapt streams for additional stackTrace argument.

pkg/mime/lib/src/mime_multipart_transformer.dart

Index: pkg/mime/lib/src/mime_multipart_transformer.dart
diff --git a/pkg/mime/lib/src/mime_multipart_transformer.dart b/pkg/mime/lib/src/mime_multipart_transformer.dart
index 581308752fd4dc45183dc9b5bee199de19663018..024cd714cd68c69a38ad7bbdca6cd12e8e2a0f8d 100644
--- a/pkg/mime/lib/src/mime_multipart_transformer.dart
+++ b/pkg/mime/lib/src/mime_multipart_transformer.dart
@@ -21,7 +21,7 @@ class _MimeMultipart extends MimeMultipart {
 
   StreamSubscription<List<int>> listen(void onData(List<int> data),
                                        {void onDone(),
-                                        void onError(error),
+                                        Function onError,
                                         bool cancelOnError}) {
     return _stream.listen(onData,
                           onDone: onDone,
@@ -138,9 +138,7 @@ class MimeMultipartTransformer
                 }
                 _controller.close();
               },
-              onError: (error) {
-                _controller.addError(error);
-              });
+              onError: _controller.addError);
         });
     return _controller.stream;
   }