Facebook does have an internal solution for push updates, I believe they use long http requests. There were some talk of relay adding support for updates via websockets, anyone have any information?
I'd think something along the lines of Surrogate Keys/Cache Tags would make sense:
- https://www.drupal.org/developing/api/8/cache/tags
- http://info.varnish-software.com/blog/advanced-cache-invalid... (ugh, they broke their site, cached at https://pinboard.in/cached/a31c4630dd2d/)
- https://www.fastly.com/blog/surrogate-keys-part-1
- https://blog.cloudflare.com/introducing-a-powerful-way-to-pu...