code: func (c *offsetCoordinator) Commit(topic string, partition int32, offset int64) error {
  	return c.commit(topic, partition, offset, "")
  }
docs: // Commit is saving offset information for given topic and partition.
  //
  // Commit can retry saving offset information on common errors. This behaviour
  // can be configured with with RetryErrLimit and RetryErrWait coordinator
  // configuration attributes.