`test_multi_actor_subs_arbiter_pub` used `run_in_actor()` to spawn
two forever-ish subscriber actors and hold their portals for a
later `cancel_actor()` (its `.result()` was commented out exactly
because `subs()` never cleanly returns). That deferred-spawn +
cancel shape isn't a blocking `to_actor.run()`, so convert to the
successor primitives (#477 removal),
- `start_actor()` per subscriber — keeps the portal for the
existing `cancel_actor()` teardown,
- run `subs()` on each via a background `Portal.run()` task in a
local `trio` nursery so both subscribe concurrently with the
test's `wait_for_actor` / topic checks,
- each bg runner swallows the `RemoteActorError`/`ContextCancelled`
that `cancel_actor()` relays; a trailing `tn.cancel_scope.cancel()`
drops any lingering runner.
Suite: 8 passed.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Gud Boi
44d730c723