golang协程如何关闭

func run(done chan int) {

        for {

                select {

                case <-done:

                        fmt.Println("exiting...")

                        done <- 1

                        break

                default:

                }

                time.Sleep(time.Second * 1)

                fmt.Println("do something")

        }

}

func main() {

        c := make(chan int)

        go run(c)

        fmt.Println("wait")

        time.Sleep(time.Second * 5)

        c <- 1

        <-c

        fmt.Println("main exited")

}