getSync method
Gets a user synchronously from cache, or returns null if not cached.
Updates the LRU access order when a user is found. Returns null if the user is not in the cache.
Implementation
User? getSync(UserID userId) {
if (_cache.containsKey(userId)) {
// Update LRU order
_accessOrder.remove(userId);
_accessOrder.add(userId);
return _cache[userId];
}
return null;
}