I believe that's one of the main reasons this won't be on by default.
It's going to be a tradeoff, either you accept that an exception can occur after sending a '200 OK' status code and possibly resort to javascript to display the error in a nice way, or you'll use the old fashioned way and send the correct response when the full page has loaded.
I'm going to use HTTP Streaming and rely on my tests and Hoptoad to fix errors as soon as they'll occur. I think the performance boost outweighs the consequence of not sending the correct status code when an exception occurs.
It's going to be a tradeoff, either you accept that an exception can occur after sending a '200 OK' status code and possibly resort to javascript to display the error in a nice way, or you'll use the old fashioned way and send the correct response when the full page has loaded.
I'm going to use HTTP Streaming and rely on my tests and Hoptoad to fix errors as soon as they'll occur. I think the performance boost outweighs the consequence of not sending the correct status code when an exception occurs.