Forking spawner + UDS transport has different timing
vs `trio_proc` — streaming example completes faster
in some cases, slower in others depending on fork
overhead + sock setup.
Deats,
- add `expect_cancel` param to `cancel_after()`, raise
`ActorTooSlowError` when cancel scope fires unexpectedly instead of
silently returning `None`.
- `time_quad_ex` fixture: bump timeout +1 for forking+UDS, explicit
`ActorTooSlowError` on `None` result instead of bare `assert results`.
- `test_not_fast_enough_quad`: `xfail` for forking+UDS being "too fast"
(cancel doesn't fire bc streaming finishes before delay).
- add `is_forking_spawner`, `tpt_proto` fixture params throughout.
Also,
- `_testing/pytest.py`: widen `start_method` parametrize and
`is_forking_spawner` fixture to `scope='session'`.
- `"""` -> `'''` docstring style throughout.
- hoist `_non_linux` to module scope (was redefined locally in two
places).
- type hints, kwarg-style `partial()` calls.
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code