Another (actually, the first) implementation of "http2-casper" (referenced in the article) can be found in h2o [https://github.com/h2o/h2o]: https://h2o.examp1e.net/configure/http2_directives.html#http...

The main author – Kazuho Oku – is to me a http2 wizard (and just now joined Fastly). You can read his thoughts on the matter: https://github.com/h2o/h2o/issues/421