@Override
    public Void call() throws IOException {
      checkMobRegionDir(regionDir);
      return null;
    }
An individual work item for parallelized mob dir processing. This is intentionally an inner
class so it can use the shared error sets and fs.
hbase-server/src/main/java/org/apache/hadoop/hbase/util/hbck/HFileCorruptionChecker.java