It doesn't work, though. We used to do long polling/comet in our app on Heroku (we axed that feature for non-technical reasons), which meant that many requests

It doesn't work, though. We used to do long polling/comet in our app on Heroku (we axed that feature for non-technical reasons), which meant that many requests were taking several minutes while the framework could still process more requests. In your system, how would you account for asynchronous web frameworks?