code: func ftGetRandomInterval(interval time.Duration) time.Duration {
  	tenPercent := int(float64(interval) * 0.10)
  	random := time.Duration(rand.Intn(tenPercent))
  	if rand.Intn(2) == 1 {
  		return interval + random
  	}
  	return interval - random
  }
docs: // ftGetRandomInterval returns a random interval with at most +/- 10%
  // of the given interval.