sidecarsForGatewayByNamespace map[string]*SidecarScope

	// mutex to protect derived sidecars i.e. not specified by user.
	derivedSidecarMutex *sync.RWMutex
}

func newSidecarIndex() sidecarIndex {
	return sidecarIndex{
		sidecarsByNamespace:           map[string][]*SidecarScope{},
		meshRootSidecarsByNamespace:   map[string]*SidecarScope{},