Detect situations when when ws subscriptions are active but no updates received

[bmuddha]

Cacher relies on the fact that cache entries have corresponding active ws subscriptions, in order to detect whether the cache entry might be stale or not. But sometimes it may be that subscription exists but no updates are being received from it, which possibly may indicate that the cache entry became stale.

There's a need for a way to detect such situations and not to serve request from cache, if it happens.

[pires]

Would instead having the subscription auto-heal be reasonable to you?