One track metadata request reached its terminal outcome.

:registered means the transport admitted the immutable metadata reply, not that the peer received it or media was authorized or delivered. :reply_failed carries the transport failure in error; other outcomes leave error nil. Owner exit terminates the connection; no event can be delivered to an owner which has exited.

Terminal handles cannot be decided again. Each request has one outcome even if its reply or best-effort stream cleanup fails. A failed reply does not roll back track registration or prevent sibling metadata replies.