code: def reindex_rethrottle(self, task_id=None, params=None):
          
          return self.transport.perform_request(
              "POST", _make_path("_reindex", task_id, "_rethrottle"), params=params
          )
docs: Change the value of ``requests_per_second`` of a running ``reindex`` task.
          `<https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html>`_
  
          :arg task_id: The task id to rethrottle
          :arg requests_per_second: The throttle to set on this request in
              floating sub-requests per second. -1 means set no throttle.