How many in-flight delegations were aborted. 0 is a legitimate SUCCESS outcome — the
work the user wanted dead may simply have finished (or never started) already.
OptionalErrorHuman-readable failure reason. Null on success.
True when the cancel request was processed (even when nothing was in flight).
Result of RealtimeClientSessionResolver.CancelRealtimeSessionTool — a structured success/failure envelope, mirroring SaveSessionChannelArtifactResult: tolerated problems (an unexpected registry error) come back as
Success: false, never a throw, while authn/ownership violations still throw like the sibling mutations.