@Override
    public Collection<MUCRoomSearchInfo> getAllRoomSearchInfo() {
        // Base the result for all rooms that are in memory, then complement with rooms in the database that haven't
        // been added yet (to catch all non-active rooms);
        return getActiveAndInactiveRooms().stream().map(MUCRoomSearchInfo::new).collect(Collectors.toList());
    }
Combine names of all rooms in the database (to catch any rooms that aren't currently in memory) with all
 names of rooms currently in memory (to include rooms that are non-persistent / never saved in the database).
 Duplicates will be removed by virtue of using a Set.

@return Names of all rooms that are known to this service.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/spi/MultiUserChatServiceImpl.java