func (s PerResource) ResolveUpdate(current *endpoint.Endpoint, candidates []*endpoint.Endpoint) *endpoint.Endpoint {
	currentResource := current.Labels[endpoint.ResourceLabelKey] // resource which has already acquired the DNS
	// TODO: sort candidates only needed because we can still have two endpoints from same resource here. We sort for consistency
	// TODO: remove once single endpoint can have multiple targets
	sort.SliceStable(candidates, func(i, j int) bool {
		return s.less(candidates[i], candidates[j])
	})
	for _, ep := range candidates {
		if ep.Labels[endpoint.ResourceLabelKey] == currentResource {
			return ep
		}
	}
	return s.ResolveCreate(candidates)
}
func (s PerResource) ResolveUpdate(current *endpoint.Endpoint, candidates []*endpoint.Endpoint) *endpoint.Endpoint {
	currentResource := current.Labels[endpoint.ResourceLabelKey] // resource which has already acquired the DNS
	// TODO: sort candidates only needed because we can still have two endpoints from same resource here. We sort for consistency
	// TODO: remove once single endpoint can have multiple targets
	sort.SliceStable(candidates, func(i, j int) bool {
		return s.less(candidates[i], candidates[j])
	})
	for _, ep := range candidates {
		if ep.Labels[endpoint.ResourceLabelKey] == currentResource {
			return ep
		}
	}
	return s.ResolveCreate(candidates)
}
// ResolveUpdate is invoked when dns name is already owned by "current" endpoint
// ResolveUpdate uses "current" record as base and updates it accordingly with new version of same resource
// if it doesn't exist then pick min