presto-main/src/main/java/io/prestosql/util/MergeSortedPages.java/PageWithPosition/appendTo
class PageWithPosition:        public void appendTo(PageBuilder pageBuilder, List<Integer> outputChannels, List<Type> outputTypes)
        {
            pageBuilder.declarePosition();
            for (int i = 0; i < outputChannels.size(); i++) {
                Type type = outputTypes.get(i);
                Block block = page.getBlock(outputChannels.get(i));
                type.appendTo(block, position, pageBuilder.getBlockBuilder(i));
            }
        }