code: func NewRandomProducer(p Producer, numPartitions int32) DistributingProducer {
  	return &randomProducer{
  		rand:       saferand{r: rand.New(rand.NewSource(time.Now().UnixNano()))},
  		producer:   p,
  		partitions: numPartitions,
  	}
  }
docs: // NewRandomProducer wraps given producer and return DistributingProducer that
  // publish messages to kafka, randomly picking partition number from range
  // [0, numPartitions)