// client is set later, it may begin rotating/renewing the client cert.
func NewKubeletClientCertificateManager(
	certDirectory string,
	nodeName types.NodeName,
	bootstrapCertData []byte,
	bootstrapKeyData []byte,
	certFile string,
	keyFile string,
	clientsetFn certificate.ClientsetFunc,
) (certificate.Manager, error) {

	certificateStore, err := certificate.NewFileStore(