Looks like they’ll be implementing it based on the Link header, which should make it trivial to implement from a developer point of view.
HTTP/2: server push.
Resources to be pushed are configured with the “http2_push” directive.
Also, preload links from the Link response headers, as described in Server Push HTTP/2 ([RFC7540]), can be pushed, if enabled with the “http2_push_preload” directive.
Only relative URIs with absolute paths can be pushed.
The number of concurrent pushes is normally limited by a client, but cannot exceed a hard limit set by the “http2_max_concurrent_pushes” directive.
Source: nginx: 641306096f5b