Re:Nginx-1.14.0 stable version has been released
by thecompilr on Wednesday April 25, 2018 @12:22PM
(#16923095)
You imply that there is a delay between the promise and the push, but it is not necessarily so. In fact the promise and the data may be sent in the same packet.
That tells the client what the server wants to send.
The client can respond with a an RST_STREAM frame https://http2.github.io/http2-spec/#RST_STREAM Again, that's a single frame.
By design it's meant to be extremely small and quick even on high latency, and/or low bandwidth connections.