Function spawn_persist_subscriber 

pub fn spawn_persist_subscriber(
    events_rx: Receiver<Event>,
    wstore: Arc<WaveStore>,
    state: Arc<Mutex<State>>,
) -> JoinHandle<()>

Spawn the persist subscriber task. Runs until the broadcast channel closes (i.e., the reducer’s bus is dropped at process shutdown). The state handle is used for workspace-scoped full-resync after a RecvError::Lagged.