代码创建一个容量为 1的缓冲通道。当通道已满时，自动收报机会丢弃时间值。
这是问题中跟踪的时间表。同一时间列出的事件按列出的顺序依次发生一点点。
1s - ticker sends value
1s - main goroutine receives first value
1s - main goroutine starts sleep for 5s
2s - ticker sends value (channel has capacity 1).
3s - ticker fails to send value because channel is full
4s - ticker fails to send value because channel is full
5s - ticker fails to send value because channel is full
6s - main goroutine exits sleep and receives buffered value
6s - ticker sends value
6s - main goroutine receives buffered value
ticker 和 main goroutine 跑到 6s 标记，因为 sleep 是 ticker 周期的倍数。在您的跟踪中，主 goroutine 赢得了比赛。在我的机器上，自动收报机赢得了比赛，我得到了你期望的时间。这是我机器上的样子。
...
5s - ticker fails to send value because channel is full
6s - ticker fails to send value because channel is full
6s - main goroutine receives buffered value
7s - ticker sends value
7s - main goroutine receives value
自动收报机在操场上以 6 秒的成绩赢得比赛。 在这里运行它。当睡眠时间减少 1µs 时，主 goroutine 赢得了比赛。在这里运行它。
当睡眠持续时间不是代码周期的倍数时，这很容易看出。以下是睡眠持续时间为 2.5 秒时发生的情况：
1s - ticker sends value
1s - main goroutine receives first value
1s - main goroutine starts sleep for 2.5s
2s - ticker sends value
3s - ticker fails to send value because channel is full
3.5s - main goroutine exits sleep and receives buffered value
4s - ticker sends value
4s - main goroutine receives value