public int getMajorVersion() {
    return 3;
  }
Create a Scanner on this file. No seeks or reads are done on creation. Call
{@link HFileScanner#seekTo(ExtendedCell)} to position an start the read. There is nothing to
clean up in a Scanner. Letting go of your references to the scanner is sufficient.
@param conf         Store configuration.
@param cacheBlocks  True if we should cache blocks read in by this scanner.
@param pread        Use positional read rather than seek+read if true (pread is better for
                    random reads, seek+read is better scanning).
@param isCompaction is scanner being used for a compaction?
@return Scanner on this file.
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/HFileReaderImpl.java