這是一個(gè)buyTicket程序，當(dāng)ticket為0時(shí)，會(huì)顯示“sell out”。我想知道為什么我不能在 buyTicket 函數(shù)中添加 sleep 以及為什么票會(huì)是負(fù)數(shù)？ func(t *Ticket) buyTicket() {        if t.getSpareTicket() <= 0 {            log.Print("sell out")            return        }        t.mu.Lock()        t.numTicket--        time.Sleep(time.Microsecond)        log.Printf("there are %d", t.numTicket)        t.mu.Unlock()    }        func (t *Ticket) getSpareTicket() int{        t.mu.Lock()        defer t.mu.Unlock()        return t.numTicket    }            func main() {        buyer := &Ticket{}        buyer.mu = sync.Mutex{}        buyer.numTicket = 100        for buyer.getSpareTicket() > 0 {            //time.Sleep(time.Microsecond)            go func() {                log.Printf("number buy a ticket")                buyer.buyTicket()            }()        }            time.Sleep(time.Second * 2)        //l := buyer.getSpareTicket()        //fmt.Println(l)    }當(dāng)我在函數(shù) buyTicket 中添加 time.sleep(time.microsecond) 時(shí)，ticket 將為負(fù)數(shù)，我想知道為什么會(huì)這樣？這是結(jié)果：2020/11/15 15:36:00 there are 22020/11/15 15:36:00 there are 12020/11/15 15:36:00 there are 02020/11/15 15:36:00 there are -12020/11/15 15:36:00 there are -22020/11/15 15:36:00 there are -32020/11/15 15:36:00 there are -42020/11/15 15:36:00 there are -5