Status MergeUntil(InternalIterator* iter,
CompactionRangeDelAggregator* range_del_agg = nullptr,
const SequenceNumber stop_before = 0,
Status MergeUntil(InternalIterator* iter,
CompactionRangeDelAggregator* range_del_agg = nullptr,
const SequenceNumber stop_before = 0,