'Stops further reading of descriptor files.'

def stop(self):

    with self._reader_thread_lock:
        self._is_stopped.set()
        self._iter_notice.set()
        try:
            while True:
                self._unreturned_descriptors.get_nowait()
        except queue.Empty:
            pass
        self._reader_thread.join()
        self._reader_thread = None
        if self._persistence_path:
            try:
                processed_files = self.get_processed_files()
                save_processed_files(self._persistence_path, processed_files)
            except:
                pass
