presto-spi/src/main/java/io/prestosql/spi/block/Int128ArrayBlockBuilder.java/Int128ArrayBlockBuilder/copyRegion
class Int128ArrayBlockBuilder:    @Override
    public Block copyRegion(int positionOffset, int length)
    {
        checkValidRegion(getPositionCount(), positionOffset, length);

        if (!hasNonNullValue) {
            return new RunLengthEncodedBlock(NULL_VALUE_BLOCK, length);
        }
        boolean[] newValueIsNull = null;
        if (hasNullValue) {
            newValueIsNull = compactArray(valueIsNull, positionOffset, length);
        }
        long[] newValues = compactArray(values, positionOffset * 2, length * 2);
        return new Int128ArrayBlock(0, length, newValueIsNull, newValues);
    }