@Override
    public void cloneFields(Cloner cloner, Object original) {
        bone = cloner.clone(bone);
        control = cloner.clone(control);
        children = cloner.clone(children);
        joint = cloner.clone(joint);
        parent = cloner.clone(parent);
        rigidBody = cloner.clone(rigidBody);
        kpTransform = cloner.clone(kpTransform);
        kpVelocity = cloner.clone(kpVelocity);
        localOffset = cloner.clone(localOffset);
    }
Callback from {@link com.jme3.util.clone.Cloner} to convert this
shallow-cloned link into a deep-cloned one, using the specified cloner
and original to resolve copied fields.

@param cloner the cloner that's cloning this link (not null)
@param original the instance from which this link was shallow-cloned
(unused)
jme3-jbullet/src/main/java/com/jme3/bullet/animation/PhysicsLink.java