internal bool TryGet(string name, out ChatRoom chatRoom) => this.ChatRooms.TryGetValue(name, out chatRoom);
 internal bool TryCreate(ChatRoomType type, uint creatorUserId, string name, string pass, string note, out ChatRoom room) => this.ChatRooms.TryAdd(name, room = new ChatRoom(type, creatorUserId, name, pass, note));