presto-spi/src/main/java/io/prestosql/spi/type/RowType.java/RowType/getObjectValue
class RowType:    @Override
    public Object getObjectValue(ConnectorSession session, Block block, int position)
    {
        if (block.isNull(position)) {
            return null;
        }

        Block arrayBlock = getObject(block, position);
        List<Object> values = new ArrayList<>(arrayBlock.getPositionCount());

        for (int i = 0; i < arrayBlock.getPositionCount(); i++) {
            values.add(fields.get(i).getType().getObjectValue(session, arrayBlock, i));
        }

        return Collections.unmodifiableList(values);
    }