async fn monotonic_append(
write_handle: &mut WriteHandle<SourceData, (), Timestamp, StorageDiff>,
updates: Vec<TimestamplessUpdate>,
at_least: Timestamp,
)async fn monotonic_append(
write_handle: &mut WriteHandle<SourceData, (), Timestamp, StorageDiff>,
updates: Vec<TimestamplessUpdate>,
at_least: Timestamp,
)