this is used in projects like Saturn/Rhea for indicating content routing error for requested content path (making it distinct from 504 which is timeout during retrieval phase)
adds missing guidance around Retry-After header, which should be leveraged for throttling (429) and in 502 and 504
(We don't need IPIP as this is filling a gap in existing specs to describe production behavior, not adding/changing anything new.)
This is a cosmetic change to Gateway spec that
Retry-Afterheader, which should be leveraged for throttling (429) and in 502 and 504(We don't need IPIP as this is filling a gap in existing specs to describe production behavior, not adding/changing anything new.)