presto-spi/src/main/java/io/prestosql/spi/block/ByteArrayBlockBuilder.java/ByteArrayBlockBuilder/writePositionTo
class ByteArrayBlockBuilder:    @Override
    public void writePositionTo(int position, BlockBuilder blockBuilder)
    {
        checkReadablePosition(position);
        blockBuilder.writeByte(values[position]);
        blockBuilder.closeEntry();
    }