virtual bool mergeBuffersPermanently(const UserId &user, const BufferId &bufferId1, const BufferId &bufferId2);
virtual void setBufferLastSeenMsg(UserId user, const BufferId &bufferId, const MsgId &msgId);
virtual QHash<BufferId, MsgId> bufferLastSeenMsgIds(UserId user);
virtual bool mergeBuffersPermanently(const UserId &user, const BufferId &bufferId1, const BufferId &bufferId2);
virtual void setBufferLastSeenMsg(UserId user, const BufferId &bufferId, const MsgId &msgId);
virtual QHash<BufferId, MsgId> bufferLastSeenMsgIds(UserId user);