code: public synchronized boolean awaitTermination(long milliseconds) 
        throws InterruptedException {
      boolean result = asyncDiskService.awaitTermination(milliseconds);
      if (result) {
        LOG.info("Deleting toBeDeleted directory.");
        for (int v = 0; v < volumes.length; v++) {
          Path p = new Path(volumes[v], TOBEDELETED);
          try {
            localFileSystem.delete(p, true);
          } catch (IOException e) {
            LOG.warn("Cannot cleanup " + p + " " + StringUtils.stringifyException(e));
          }
        }
      }
      return result;
    }
docs: Wait for the termination of the thread pools.
  
  @param milliseconds  The number of milliseconds to wait
  @return   true if all thread pools are terminated within time limit
  @throws InterruptedException