Function flush_batch 

pub(crate) async fn flush_batch(
    flush: Batch,
    partition_manager: &(impl PhysicalFlushPartitionProvider + ?Sized),
    write_dispatcher: &(impl PhysicalFlushWriteDispatcher + ?Sized),
    catalog_manager: &(impl PhysicalFlushCatalogProvider + ?Sized),
    flow_notification_tx: FlowNotifier,
)

Flushes a batch and reports completion to its waiters.