presto-spi/src/main/java/io/prestosql/spi/block/LazyBlock.java/PositionLazyBlockLoader/PositionLazyBlockLoader
class PositionLazyBlockLoader:        public PositionLazyBlockLoader(LazyData delegate, int[] positions, int offset, int length)
        {
            this.delegate = requireNonNull(delegate, "delegate is null");
            this.positions = requireNonNull(positions, "positions is null");
            this.offset = offset;
            this.length = length;
        }