@Override
  public void abort(String why, Throwable e) {
    if (this.aborted) {
      return;
    }

    this.aborted = true;
    LOG.warn("Aborting because: " + why, e);
    this.executor.shutdownNow();
  }
Attempt to cleanly shutdown any running tasks - allows currently running tasks to cleanly
finish
hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/regionserver/LogRollBackupSubprocedurePool.java