code: public T copy (Kryo kryo, T original) {
  		if (isImmutable()) return original;
  		throw new KryoException("Serializer does not support copy: " + getClass().getName());
  	}
docs: Returns a copy of the specified object. The default implementation returns the original if {@link #isImmutable()} is true,
  else throws {@link KryoException}. Subclasses can optionall override this method to support {@link Kryo#copy(Object)}.
  <p>
  Before Kryo can be used to copy child objects, {@link Kryo#reference(Object)} must be called with the copy to ensure it can
  be referenced by the child objects. A serializer that uses {@link Kryo} to copy a child object may need to be reentrant.
  <p>
  This method should not be called directly, instead this serializer can be passed to {@link Kryo} copy methods that accept a
  serialier.