presto-spi/src/main/java/io/prestosql/spi/block/Int128ArrayBlock.java/Int128ArrayBlock/copyRegion
class Int128ArrayBlock:    @Override
    public Block copyRegion(int positionOffset, int length)
    {
        checkValidRegion(getPositionCount(), positionOffset, length);

        positionOffset += this.positionOffset;
        boolean[] newValueIsNull = valueIsNull == null ? null : compactArray(valueIsNull, positionOffset, length);
        long[] newValues = compactArray(values, positionOffset * 2, length * 2);

        if (newValueIsNull == valueIsNull && newValues == values) {
            return this;
        }
        return new Int128ArrayBlock(0, length, newValueIsNull, newValues);
    }