/**
   * Lifecycle method invoked when the consumer has destroyed. Erase the reference to the dropbox
   * low level client
   *
   * @throws Exception
   */
  @Override
  protected void doStop() throws Exception {
    if (configuration.getClient() == null) {
      configuration.setClient(null);

      LOG.info("consumer dropbox client deleted");
    }
    super.doStop();
  }