BuildClusters(node *model.Proxy, req *model.PushRequest) ([]*discovery.Resource, model.XdsLogDetails)

	// BuildDeltaClusters returns both a list of resources that need to be pushed for a given proxy and a list of resources
	// that have been deleted and should be removed from a given proxy. This is Delta CDS output.
	BuildDeltaClusters(proxy *model.Proxy, updates *model.PushRequest,

	if !cdsNeedsPush(req, proxy) {
		return nil, nil, model.DefaultXdsLogDetails, false, nil
	}
	updatedClusters, removedClusters, logs, usedDelta := c.ConfigGenerator.BuildDeltaClusters(proxy, req, w)
	return updatedClusters, removedClusters, logs, usedDelta, nil

func (f *ConfigGenTest) DeltaClusters(
	p *model.Proxy,
	configUpdated sets.Set[model.ConfigKey],
	watched *model.WatchedResource,
) ([]*cluster.Cluster, []string, bool) {
	raw, removed, _, delta := f.ConfigGen.BuildDeltaClusters(p,
		&model.PushRequest{
			Push: f.PushContext(), ConfigsUpdated: configUpdated,
		}, watched)
	res := make([]*cluster.Cluster, 0, len(raw))
	for _, r := range raw {
		c := &cluster.Cluster{}

	}
	return configgen.buildClusters(proxy, req, services)
}

// BuildDeltaClusters generates the deltas (add and delete) for a given proxy. Currently, only service changes are reflected with deltas.
// Otherwise, we fall back onto generating everything.
func (configgen *ConfigGeneratorImpl) BuildDeltaClusters(proxy *model.Proxy, updates *model.PushRequest,
	watched *model.WatchedResource,