@Override
  public synchronized void cleanup() {
    super.cleanup();
    stopHFileDeleteThreads();
  }
Construct an {@link HFileDeleteTask} for each file to delete and add into the correct queue
@param file the file to delete
@return HFileDeleteTask to track progress
hbase-server/src/main/java/org/apache/hadoop/hbase/master/cleaner/HFileCleaner.java