code: func (ct *costTracker) printStats() {
  	if ct.stats == nil {
  		return
  	}
  	for code, arr := range ct.stats {
  		log.Info("Request cost statistics", "code", code, "1/16", arr[0], "1/8", arr[1], "1/4", arr[2], "1/2", arr[3], "1", arr[4], "2", arr[5], "4", arr[6], "8", arr[7], "16", arr[8], ">16", arr[9])
  	}
  }
docs: // printStats prints the distribution of real request cost relative to the average estimates