pubsub.go
func (p *PubSub) UnregisterTopicValidator(topic string) error {
	rmVal := &rmValReq{
		topic: topic,
		resp:  make(chan error, 1),
	}

	p.rmVal <- rmVal
	return <-rmVal.resp
}
func (p *PubSub) UnregisterTopicValidator(topic string) error {
	rmVal := &rmValReq{
		topic: topic,
		resp:  make(chan error, 1),
	}

	p.rmVal <- rmVal
	return <-rmVal.resp
}
// UnregisterTopicValidator removes a validator from a topic.
// Returns an error if there was no validator registered with the topic.