code: func SetRetrier(retrier Retrier) ClientOptionFunc {
  	return func(c *Client) error {
  		if retrier == nil {
  			retrier = noRetries // no retries by default
  		}
  		c.retrier = retrier
  		return nil
  	}
  }
docs: // SetRetrier specifies the retry strategy that handles errors during
  // HTTP request/response with Elasticsearch.