code: func (c *StatsdClient) IncrWithSampling(stat string, count int64, sampleRate float32) error {
  	if err := checkSampleRate(sampleRate); err != nil {
  		return err
  	}
  
  	if !shouldFire(sampleRate) {
  		return nil // ignore this call
  	}
  
  	if err := checkCount(count); err != nil {
  		return err
  	}
  
  	return c.send(stat, "%d|c", count, sampleRate)
  }
docs: // IncrWithSampling - Increment a counter metric with sampling between 0 and 1