in retrospect it seems the semantics got overcomplicated, which led to partial implementations (and of course many bugs and confusing and hard technical questio

in retrospect it seems the semantics got overcomplicated, which led to partial implementations (and of course many bugs and confusing and hard technical questions), which eventually led to implementation projects getting abandoned. and, probably in situations where the benefit of decreasing "time to first render" is big enough, there it makes sense to have a server that is coupled to the various low-level bits (load balancer connection tracking info, TLS session info, User Agent header, and Cookie of course) and for new sessions it can produce an optimized response payload.