code: public <T> void registerSerializableClass(final Class<T> clazz, final Serializer<T> serializer) {
          kryo.registerSerializableClass(clazz, serializer);
      }
docs: Registers a class that may be send over the network.
  
  Use this method only before the first invocation of either {@link KryoSerializer#serialize(List)} or
  {@link KryoSerializer#deserialize(byte[])}. If you invoke it after these methods it is not guaranteed that the
  {@link Kryo} used by these methods will actually use your serializers.
  
  @param clazz The class that's maybe send.
  @param serializer An optional serializer for this class. If it's null than the default serialization of kryo
  is used.
  @param <T> see clazz parameter.