先看例子： package mainimport ("fmt""math/rand""sync""time")var wg sync.WaitGroupfunc hello(i int) {defer wg.Done()fmt.Println("hello go", i)}func main() {for i := 0; i < 10; i++ {wg.Add(i)go hello(i)}

The best book I’ve read on sleep is Matthew Walker’s Why We Sleep. In it, he explains the importance of getting good sleep as well as offers suggestions for how to avoid problems of nighttime insomn

先看例子： package mainimport ("fmt""math/rand""sync""time")var wg sync.WaitGroupfunc hello(i int) {defer wg.Done()fmt.Println("hello go", i)}func main() {for i := 0; i < 10; i++ {wg.Add(i)go hello(i)}