code: public static void deleteRecursive(@Nonnull File dir) throws IOException {
          deleteRecursive(fileToPath(dir), PathRemover.PathChecker.ALLOW_ALL);
      }
docs: Deletes the given directory (including its contents) recursively.
  It does not take no for an answer - if necessary, it will have multiple
  attempts at deleting things.
  
  @throws IOException
  if the operation fails.