func formatDuration has a bug will to output wrong result about go-astisub HOT 4 CLOSED

import 	"github.com/shopspring/decimal"

// formatDuration formats a duration
func formatDuration(i time.Duration, millisecondSep string, numberOfMillisecondDigits int) (s string) {
	// Parse hours
	var hours = int(i / time.Hour)
	var n = i % time.Hour
	if hours < 10 {
		s += "0"
	}
	s += strconv.Itoa(hours) + ":"

	// Parse minutes
	var minutes = int(n / time.Minute)
	n = i % time.Minute
	if minutes < 10 {
		s += "0"
	}
	s += strconv.Itoa(minutes) + ":"

	// Parse seconds
	var seconds = int(n / time.Second)
	n = i % time.Second
	if seconds < 10 {
		s += "0"
	}
	s += strconv.Itoa(seconds) + millisecondSep

	// Parse milliseconds
	var milliseconds = float64(n/time.Millisecond) / float64(1000)
	// PCT 解决精度丢失问题
	decimalMs := decimal.NewFromFloat(milliseconds)
	round := decimalMs.RoundFloor(int32(numberOfMillisecondDigits)).InexactFloat64()
	s += fmt.Sprintf("%."+strconv.Itoa(numberOfMillisecondDigits)+"f", round)[2:]
	// s += fmt.Sprintf("%."+strconv.Itoa(numberOfMillisecondDigits)+"f", milliseconds)[2:]
	return
}