func main() {
    rand.Seed(time.Now().Unix())
    ctx, cancelFunc := context.WithCancel(context.Background())
    anies := make(chan any)
    go doSomething(ctx, anies)
    intn := rand.Intn(2)
    if intn == 0 { //BRANCH1
        cancelFunc()
        close(anies) 
    }
    time.Sleep(time.Second)
}

func doSomething(ctx context.Context, anies chan any) {
    for {
         if ctx.Err() == nil { //LINE2
            anies <- 1 //LINE3
        }
    }
}

有没有可能BRANCH1发生在2号线和3号线之间，我会很恐慌。