Comment by tannhaeuser

I agree these things can be useful, but again none of these come out of the box (if I haven't overlooked or misunderstood something). Including "doing the naive thing"; I mean how do you expect your web server to automatically push CSS or SVG sprites/fonts unless you're relying on the server to intercept/parse your HTML for delivery-time optimizations a la PageSpeed and make heuristic scheduling decisions? Unless you're putting in the effort to optimize your payloads you will just result in as many roundtrips with HTTP/1.1 + keep-alive.