presto-main/src/main/java/io/prestosql/operator/aggregation/arrayagg/LegacyArrayAggregationGroupState.java/LegacyArrayAggregationGroupState/isEmpty
class LegacyArrayAggregationGroupState:    @Override
    public boolean isEmpty()
    {
        BlockBuilder blockBuilder = blockBuilders.get(getGroupId());
        verify(blockBuilder.getPositionCount() != 0);
        return false;
    }