func TestCodeRes(t *testing.T)  {
	require := make(chan int, 5)

	for i := 0; i < 5; i++ {
		require <- i
	}

    //关闭 require
	close(require)

	//设置定时器控制读取速率
	ti := time.Tick(time.Duration(1) * time.Second)

	//直接range只会读取值，缓冲区无数据会读取默认零值，chan关闭，则退出range
	for i := range require {
		<-ti
		fmt.Printf("i: %d time: %v\n", i, time.Now())
	}

	//	=== RUN   TestCodeRes
    // i: 0 time: 2022-10-23 20:06:52.6746003 +0800 CST m=+1.026004901
    // i: 1 time: 2022-10-23 20:06:53.6702704 +0800 CST m=+2.021675001
    // i: 2 time: 2022-10-23 20:06:54.6643626 +0800 CST m=+3.015767201
    // i: 3 time: 2022-10-23 20:06:55.6645058 +0800 CST m=+4.015910401
    // i: 4 time: 2022-10-23 20:06:56.6647772 +0800 CST m=+5.016181801
    //	--- PASS: TestCodeRes (5.01s)
    //	PASS

    结论：close()，会在最后一个send的值被receive了以后执行，这里就是 for range 循环完以后执行。通过官方文档的介绍也是可以知道的


    // The close built-in function closes a channel, which must be either
    // bidirectional or send-only. It should be executed only by the sender,
    // never the receiver, and has the effect of shutting down the channel after
    // the last sent value is received. After the last value has been received
    // from a closed channel c, any receive from c will succeed without
    // blocking, returning the zero value for the channel element. The form
    //	x, ok := <-c
    // will also set ok to false for a closed channel.
    func close(c chan<- Type)
}