onPriorityUserList

Returns a user list sorted by priority (lower position = lower priority). Notes:

1. When the total subscriptions exceed the limit, the first OnLineStatusManager#DEFAULT_SUBSCRIBE_NUMBER users are kept; users not in the list but already subscribed will be unsubscribed, and users in the list but not yet subscribed will be subscribed.

2. To prevent a user ID from being evicted when the limit is exceeded, place it near the front of the list.

3. The SDK caches the last returned data; call OnLineStatusManager#clearPriorityUserList to clear the cache.