code: func roundIntStr(numNextDot byte, intStr string) string {
  	if numNextDot < '5' {
  		return intStr
  	}
  	retStr := []byte(intStr)
  	for i := len(intStr) - 1; i >= 0; i-- {
  		if retStr[i] != '9' {
  			retStr[i]++
  			break
  		}
  		if i == 0 {
  			retStr[i] = '1'
  			retStr = append(retStr, '0')
  			break
  		}
  		retStr[i] = '0'
  	}
  	return string(retStr)
  }
docs: // roundIntStr is to round int string base on the number following dot.