code: func (ingressStatusStrategy) PrepareForUpdate(ctx context.Context, obj, old runtime.Object) {
  	newIngress := obj.(*networking.Ingress)
  	oldIngress := old.(*networking.Ingress)
  	// status changes are not allowed to update spec
  	newIngress.Spec = oldIngress.Spec
  }
docs: // PrepareForUpdate clears fields that are not allowed to be set by end users on update of status