facebook/tornado — pull request #540 by zhuzhuor (2012-06-18 02:36:10+00:00)
Title: A simple fix for the bug RequestHandler.add_header doesn't work for WSGI application

The wsgi.WSGIApplication.__call__ function forgets to include handler._list_headers (which is made by RequestHandler.add_header) as a part of its response headers.

Thanks