}
	if config.Meta == nil {
		n.Metadata = &pstruct.Struct{
			Fields: map[string]*pstruct.Value{
				"ISTIO_VERSION": {Kind: &pstruct.Value_StringValue{StringValue: "65536.65536.65536"}},
			},
		}
	} else {
		n.Metadata = config.Meta
		if config.Meta.Fields["ISTIO_VERSION"] == nil {
			config.Meta.Fields["ISTIO_VERSION"] = &pstruct.Value{Kind: &pstruct.Value_StringValue{StringValue: "65536.65536.65536"}}
		}
	}
	return n

	t.Helper()
	ads := s.ConnectADS().WithID(sidecarID)

	metadata := &structpb.Struct{Fields: map[string]*structpb.Value{
		"ISTIO_VERSION": {Kind: &structpb.Value_StringValue{StringValue: "1.3"}},
		"NETWORK":       {Kind: &structpb.Value_StringValue{StringValue: network}},
	}}

	ads.RequestResponseAck(t, &discovery.DiscoveryRequest{
		Node: &core.Node{

          "id": "waypoint~192.168.252.229~httpbin-istio-waypoint-58f646c5ff-dbfkz.default~default.svc.cluster.local",
          "metadata": {
            "ISTIO_PROXY_SHA": "ee85c5f28702f00621aed895915fca565796b9e4",
            "ISTIO_VERSION": "1.21.0-1226",
            "metadata": {
              "build.type": "RELEASE",
              "build.label": "dev",
              "revision.sha": "ee85c5f28702f00621aed895915fca565796b9e4",

			option: option.NodeMetadata(&model.BootstrapNodeMetadata{
				NodeMetadata: model.NodeMetadata{
					IstioVersion: "fake",
				},
			}, map[string]any{
				"key": "value",
			}),
			expected: "{\"ISTIO_VERSION\":\"fake\",\"key\":\"value\"}",
		},
		{
			testName: "discovery address",
			key:      "discovery_address",
			option:   option.DiscoveryAddress("fake"),
			expected: "fake",
		},
		{

	// this field should be preferred if it is present.
	ProxyConfig *NodeMetaProxyConfig `json:"PROXY_CONFIG,omitempty"`

	// IstioVersion specifies the Istio version associated with the proxy
	IstioVersion string `json:"ISTIO_VERSION,omitempty"`

	// IstioRevision specifies the Istio revision associated with the proxy.
	// Mostly used when istiod requests the upstream.
	IstioRevision string `json:"ISTIO_REVISION,omitempty"`

	ProxyType            model.NodeType `json:"proxy_type,omitempty"`
	ProxyVersion         string         `json:"proxy_version,omitempty"`
	IstioVersion         string         `json:"istio_version,omitempty"`
	ClusterSent          string         `json:"cluster_sent,omitempty"`
	ClusterAcked         string         `json:"cluster_acked,omitempty"`
	ListenerSent         string         `json:"listener_sent,omitempty"`