code: private boolean isRecursiveDeleteSafe(@Nullable AlluxioURI alluxioUri) {
      if (alluxioUri == null || !alluxioUri.toString().startsWith(mRootPath.toString())) {
        // Path is not part of sub-tree being deleted
        return false;
      }
      if (mUfsSyncChecker == null) {
        // Delete is unchecked
        return true;
      }
      return mUfsSyncChecker.isDirectoryInSync(alluxioUri);
    }
docs: Check if recursively deleting from the UFS is "safe".
  
  @param alluxioUri Alluxio path to delete
  @return true, if path can be deleted recursively from UFS; false, otherwise