WithTimeOut 超时退出返回 nil, 注意 func 返回值不能是 any From: https://geektutu.com/post/hpg-timeout-goroutine.html WithTimeOut(800*time.Millisecond, func () int { time.Sleep(time.Millisecond) return 1 }) // 1 WithTimeOut(800*time.Millisecond, func () string { time.Sleep(time.Second) return "2" }) // nil.