App Engine has supported the X-Associated-Content header for a little while now, and also supports the Link header, with rel=preload, like:
Link: <https://example.com/other/styles.css>; rel=preload; as=style
The experiments described in this post were conducted early this year, and it looks like those developments are fairly new?
I just discovered this too: https://github.com/GoogleChrome/http2push-gae
Is this new-ish capability documented somewhere?
App Engine has supported the X-Associated-Content header for a little while now, and also supports the Link header, with rel=preload, like:
See http://w3c.github.io/preload/