f1273ed704
_SESSION_CACHE_MAX_SIZE was assigned twice with two comments describing one constant. _retain_for_retry and _keep_until_flushed shared the has-unsynced / current-owner / reclaim body and differed only in what to do when a newer object owns the key; _reclaim_key_locked returns that owner and each caller keeps its tail. _ensure_async_writer had no production caller (save() uses the _locked form under _async_thread_lock); removed, tests retargeted, constructor comment fixed. shutdown() sets _shutting_down under _async_thread_lock like the other site so save()'s flag check and the enqueue cannot interleave with it. tests/test_honcho_session_cache_bounds.py hoists its mid-file imports.