presto-main/src/main/java/io/prestosql/operator/aggregation/arrayagg/SingleArrayAggregationState.java/SingleArrayAggregationState/add
class SingleArrayAggregationState:    @Override
    public void add(Block block, int position)
    {
        if (blockBuilder == null) {
            blockBuilder = type.createBlockBuilder(null, 16);
        }
        type.appendTo(block, position, blockBuilder);
    }