Function add_updates_yielding 

async fn add_updates_yielding(
    builder: &mut BatchBuilder<SourceData, (), Timestamp, StorageDiff>,
    updates: &[TimestamplessUpdate],
    ts: Timestamp,
)

Adds updates to builder at time ts, yielding to the Tokio runtime after every MONOTONIC_APPEND_YIELD_UPDATES updates or MONOTONIC_APPEND_YIELD_BYTES bytes of row data, whichever comes first.