}
	key, cert := agent.GetKeyCertsForXDS()
	return &istiogrpc.TLSOptions{
		RootCert:      xdsCACertPath,
		Key:           key,
		Cert:          cert,
		ServerAddress: agent.proxyConfig.DiscoveryAddress,
		SAN:           p.istiodSAN,
	}, nil
}

// tapRequest() sends "req" to Istiod, and returns a matching response, or `nil` on timeout.