presto-orc/src/main/java/io/prestosql/orc/AbstractOrcDataSource.java/LazyBufferLoader/loadNestedDiskRangeBuffer
class LazyBufferLoader:        public Slice loadNestedDiskRangeBuffer(DiskRange nestedDiskRange)
        {
            load();

            checkArgument(diskRange.contains(nestedDiskRange));
            int offset = toIntExact(nestedDiskRange.getOffset() - diskRange.getOffset());
            return bufferSlice.slice(offset, nestedDiskRange.getLength());
        }