pub(super) fn start_worker(
key: BatchKey,
worker_tx: Sender<WorkerCommand>,
workers: Arc<WorkerRegistry<BatchKey, WorkerCommand>>,
rx: Receiver<WorkerCommand>,
shutdown: Sender<()>,
flush_policy: TimingFlushPolicy,
flush_limiter: FlushLimiter,
inserter: Arc<Inserter>,
notifier: FlowNotifier,
idle_timeout: Duration,
)