[Rust][Arrow] Move explicit close into supervisor

rust/NEXT_CHANGELOG.md

@@ -18,9 +18,17 @@
   the full replay completes and ACK processing can resume on the replacement
   connection.
 - Arrow Flight rejects unrepresentable timeout values: stream creation returns
-  `InvalidArgument` when ACK or recovery deadlines exceed the platform
+  `InvalidArgument` when ACK, recovery, or flush deadlines exceed the platform
   monotonic-clock range. Server-advertised graceful-rotation periods are capped
   at one year.
+- Arrow Flight close is cancellation-safe and half-closes the active request before
+  bounded response draining. ACK success is decided when the durable watermark is
+  applied relative to the original flush deadline. Close during recovery cancels the
+  attempt, retains the unacknowledged suffix, and returns the error that triggered the
+  current attempt. Close during an existing recovery or server-requested rotation keeps
+  that trigger even if every record is durable, so an error can coexist with an empty
+  unacknowledged-batch set. After a request-send failure, one ready response may still
+  be applied; later stream items are not discarded in order to start recovery.
 - Fixed Arrow Flight recovery sender lifetime: replacement senders are now published
   only after pending replay succeeds, while initial supervisor handoff and failed or
   cancelled replay promptly drop redundant senders instead of retaining incomplete