code: public static void registerSerializers( final Kryo kryo ) {
          final UnmodifiableCollectionsSerializer serializer = new UnmodifiableCollectionsSerializer();
          UnmodifiableCollection.values();
          for ( final UnmodifiableCollection item : UnmodifiableCollection.values() ) {
              kryo.register( item.type, serializer );
          }
      }
docs: Creates a new {@link UnmodifiableCollectionsSerializer} and registers its serializer
  for the several unmodifiable Collections that can be created via {@link Collections},
  including {@link Map}s.
  
  @param kryo the {@link Kryo} instance to set the serializer on.
  
  @see Collections#unmodifiableCollection(Collection)
  @see Collections#unmodifiableList(List)
  @see Collections#unmodifiableSet(Set)
  @see Collections#unmodifiableSortedSet(SortedSet)
  @see Collections#unmodifiableMap(Map)
  @see Collections#unmodifiableSortedMap(SortedMap)