func NewTimer() *Timer {
	return &Timer{time.Now()}
}
NewTimer creates a minimal timer.
package util
import (
	"os"
	"strconv"
	"strings"
	"time"
)
func ToFixed(n float64, prec int) string {
	s := strconv.FormatFloat(n, 'f', prec, 64)
	return strings.TrimRight(strings.TrimRight(s, "0"), ".")
}
func IsFileExist(fileName string) bool {
	_, err := os.Stat(fileName)
	if os.IsNotExist(err) {
		return false
	}
	return true
}
type Timer struct {
	startAt time.Time
}