code: func NewOffsetCoordinatorConf(consumerGroup string) OffsetCoordinatorConf {
  	return OffsetCoordinatorConf{
  		ConsumerGroup: consumerGroup,
  		RetryErrLimit: 10,
  		RetryErrWait:  time.Millisecond * 500,
  		Logger:        nil,
  	}
  }
docs: // NewOffsetCoordinatorConf returns default OffsetCoordinator configuration.