1.併發
var waitGroup = new(sync.WaitGroup)
waitGroup.Add(num)
waitGroup.Wait()
func xxx(){
	...
	waitGroup.Done()
}

2.列印程式碼處理時間
func TimeCost(str string, start time.Time) {
	terminal := time.Since(start)
	fmt.Println(str, terminal)
}
func xxx(){
	defer common.TimeCost("本次執行時間：", time.Now())
	...
}

3.判斷key是否在map中
if v, ok := m[key];ok{
	存在
}

4.斷言
if backtime, ok := LS[uuid][cid].Ele.Back().Value.(int); !ok {
	fmt.Fprintf(os.Stderr, "斷言失敗")
	return
}