select 与 time.After 配合使用的问题

今天在工作中发现了一个有趣的现象。

在一个select中设定了两个定时器，本来预计哪个定时器到达就运行相应指令的，但是发现最终只有时间最短的定时器一直得到执行，其它定时器完全没有得到执行。

package main

import (
"fmt"
"time"
)

func main(){
    for i:=0; i< 3;i ++ {
        select{
            case <-time.After(7*time.Second):
                fmt.Println("1 second")
                
            case <-time.After(5*time.Second):
                fmt.Println("8 seconds")
        }
    }
}

服务器输出是：

8 seconds
8 seconds
8 seconds

在stackoverflow上有人提到了，time.After每次都会返回一个新的channel，所以select不可能监测到新产生的channel：
https://stackoverflow.com/questions/39212333/how-can-i-use-time-after-and-default-in-golang

package main

import (
"fmt"
"time"
)

func main(){
    count := 0
    timeout1 := time.After(7*time.Second)
    timeout2 := time.After(5*time.Second)
    for i:=0; i< 36; i++{
        select{
            case <-timeout1:
                fmt.Println(count, "7 second")
                
            case <-timeout2:
                fmt.Println(count, "5 seconds")
                
            default:
                fmt.Println(count, "Just wait")
                
        }
        count++
        time.Sleep(1*time.Second)
    }
}

0 Just wait
1 Just wait
2 Just wait
3 Just wait
4 Just wait
5 5 seconds 6 Just wait 7 7 second 8 Just wait 9 Just wait 10 Just wait 11 Just wait 12 Just wait 13 Just wait 14 Just wait 15 Just wait 16 Just wait 17 Just wait 18 Just wait 19 Just wait 20 Just wait 21 Just wait 22 Just wait 23 Just wait 24 Just wait 25 Just wait 26 Just wait 27 Just wait 28 Just wait 29 Just wait 30 Just wait 31 Just wait 32 Just wait 33 Just wait 34 Just wait 35 Just wait