根据当前时间计算出前15分钟的开始和结束时间

func getBefore15MinuteTime() (uint, uint) {
   var startAt, endAt int
   currentTime := time.Now()
   now := int(currentTime.Unix())
   minute := currentTime.Minute()
   second := currentTime.Second()
   extraMinute := minute % 15
   endAt = now - extraMinute*60 - second - 1
   startAt = endAt - 15*60 + 1
   return uint(startAt), uint(endAt)
}