presto-spi/src/main/java/io/prestosql/spi/PageBuilder.java/PageBuilder/reset
class PageBuilder:    public void reset()
    {
        if (isEmpty()) {
            return;
        }
        pageBuilderStatus = new PageBuilderStatus(pageBuilderStatus.getMaxPageSizeInBytes());

        declaredPositions = 0;

        for (int i = 0; i < types.size(); i++) {
            blockBuilders[i] = blockBuilders[i].newBlockBuilderLike(pageBuilderStatus.createBlockBuilderStatus());
        }
    }