I found some solution. According to Reapplying Subscriptions on Reconnect
If a client is using a Temporary Queue and disconnects for over a minute, the Temporary Queue will be removed from the event broker, and automatically recreated once the client reconnects. However, the subscription will not be re-applied even if REAPPLY_SUBSCRIPTIONS is enabled. my temporary queue won’t have any subscriptions if it was recreated.
So I’ll initially add dummy subscription immediately after creating a flow. Then after reconnect I can try adding the dummy subscription again and if I get error SubscriptionAlreadyPresent then I know for sure that the queue wasn’t destroyed.
With this solution I could still lose messages because they don’t fit into the queue because of small quota.
Wondering whether there’s a better solution?