presto-orc/src/main/java/io/prestosql/orc/CachingOrcDataSource.java/CachingOrcDataSource/CachingOrcDataSource
class CachingOrcDataSource:    public CachingOrcDataSource(OrcDataSource dataSource, RegionFinder regionFinder)
    {
        this.dataSource = requireNonNull(dataSource, "dataSource is null");
        this.regionFinder = requireNonNull(regionFinder, "regionFinder is null");
        this.cache = Slices.EMPTY_SLICE;
    }