presto-spi/src/main/java/io/prestosql/spi/block/ColumnarMap.java/ColumnarMap/ColumnarMap
class ColumnarMap:    private ColumnarMap(Block nullCheckBlock, int offsetsOffset, int[] offsets, Block keysBlock, Block valuesBlock)
    {
        this.nullCheckBlock = nullCheckBlock;
        this.offsetsOffset = offsetsOffset;
        this.offsets = offsets;
        this.keysBlock = keysBlock;
        this.valuesBlock = valuesBlock;
    }