presto-main/src/main/java/io/prestosql/operator/index/StreamingIndexedData.java/StreamingIndexedData/appendTo
class StreamingIndexedData:    @Override
    public void appendTo(long position, PageBuilder pageBuilder, int outputChannelOffset)
    {
        // TODO: use the code generator here
        checkState(currentPage != null, "getJoinPosition not called first");
        int intPosition = toIntExact(position);
        for (int i = 0; i < outputTypes.size(); i++) {
            Type type = outputTypes.get(i);
            Block block = currentPage.getBlock(i);
            BlockBuilder blockBuilder = pageBuilder.getBlockBuilder(i + outputChannelOffset);
            type.appendTo(block, intPosition, blockBuilder);
        }
    }