code: public static void deleteDirectory(File directory) throws IOException {
  		checkNotNull(directory, "directory");
  
  		guardIfWindows(FileUtils::deleteDirectoryInternal, directory);
  	}
docs: Deletes the given directory recursively.
  
  <p>If the directory does not exist, this does not throw an exception, but simply does nothing.
  It considers the fact that a directory-to-be-deleted is not present a success.
  
  <p>This method is safe against other concurrent deletion attempts.
  
  @param directory The directory to be deleted.
  @throws IOException Thrown if the given file is not a directory, or if the directory could not be
  deleted for some reason, for example due to missing access/write permissions.