code: func (ref *Config) ValidateConsumerConfig() error {
  	if ref.Brokers == nil {
  		return errors.New("invalid Brokers - one or more brokers must be specified")
  	}
  	if ref.GroupID == "" {
  		return errors.New("invalid GroupID - no GroupID specified")
  	}
  	if ref.RecvNotification && ref.RecvNotificationChan == nil {
  		return errors.New("notification channel not specified")
  	}
  	if ref.RecvError && ref.RecvErrorChan == nil {
  		return errors.New("error channel not specified")
  	}
  	if ref.RecvMessageChan == nil {
  		return errors.New("recvMessageChan not specified")
  	}
  	return ref.ConsumerConfig().Validate()
  }
docs: // ValidateConsumerConfig validates config for Consumer