errormiddleware does not return result of start_response

[kalmes]

start_response returns a writer that may be used to begin writing response content. Unfortunately, ResponseStartChecker does not return the result of start_response, and prevents this from working. This causes problems when wrapping paste.cgiapp.CGIApplication for instance.

It would be nice to provide a wrapper for the writer function. But even without going that far, ReponseStartChecker._ _call_ _ can be fixed by changing:

        self.response_started = True
        self.start_response(*args)

to:

        self.response_started = True
        return self.start_response(*args)

(I am new to wsgi development, so please correct me if I am misunderstanding.)