default String onMapChangeBatchEnd(final long processedCount) {
        //default implementation does nothing
        return null;
    }
Optional method which is called after a batch of map layer updates (add/remove). It is intended to
 be used to trigger a "global map view update" if this is required by map implementation
main/src/main/java/cgeo/geocaching/unifiedmap/geoitemlayer/IProviderGeoItemLayer.java