public static <Key, Value> LazyObjectMap<Key, ObjectSet<Value>> newMapOfSets() {
        final ObjectProvider<ObjectSet<Value>> provider = SetObjectProvider.getProvider();
        return newMap(provider);
    }
public static < Key , Value > LazyObjectMap < Key , ObjectSet < Value > > newMapOfSets ( ) { final ObjectProvider < ObjectSet < Value > > provider = SetObjectProvider . getProvider ( ) ; return newMap ( provider ) ; }
@return a new lazy map that provides empty object sets.
@param <Key> type of map keys.
@param <Value> type of set values.