// `apiGroups:["apps"], apiVersions:["v1"], resources: ["deployments"]` and `matchPolicy: Equivalent`,
  // an API request to apps/v1beta1 deployments would be converted and sent to the webhook
  // with `kind: {group:"apps", version:"v1", kind:"Deployment"}` (matching the rule the webhook registered for),

  // `apiGroups:["apps"], apiVersions:["v1"], resources: ["deployments"]` and `matchPolicy: Equivalent`,
  // an API request to apps/v1beta1 deployments would be converted and sent to the webhook
  // with `kind: {group:"apps", version:"v1", kind:"Deployment"}` (matching the rule the webhook registered for),

// +protobuf=true
// +k8s:openapi-gen=true
message Unknown {
  optional TypeMeta typeMeta = 1;

  // Raw will hold the complete serialized object which couldn't be matched
  // with a registered type. Most likely, nothing should be done with this
  // except for passing it through the system.
  optional bytes raw = 2;

  // ContentEncoding is encoding used to encode 'Raw' data.

)

const (
	// Location to read istioctl defaults from
	defaultIstioctlConfig = "$HOME/.istioctl/config.yaml"
)

var (
	// IstioConfig is the name of the istioctl config file (if any)
	IstioConfig = env.Register("ISTIOCONFIG", defaultIstioctlConfig,
		"Default values for istioctl flags").Get()

	LoggingOptions = defaultLogOptions()

	LogFormat  = "log"
	JSONFormat = "json"
	YAMLFormat = "yaml"
)

var (
	MsgOutputFormatKeys = []string{LogFormat, JSONFormat, YAMLFormat}
	MsgOutputFormats    = make(map[string]bool)
	termEnvVar          = env.Register("TERM", "", "Specifies terminal type.  Use 'dumb' to suppress color output")
)

func init() {
	for _, key := range MsgOutputFormatKeys {
		MsgOutputFormats[key] = true
	}
}

	"istioNamespace":      env.Register("ISTIOCTL_ISTIONAMESPACE", constants.IstioSystemNamespace, "The istioctl --istioNamespace override"),
	"xds-address":         env.Register("ISTIOCTL_XDS_ADDRESS", "", "The istioctl --xds-address override"),
	"xds-port":            env.Register("ISTIOCTL_XDS_PORT", 15012, "The istioctl --xds-port override"),
	"authority":           env.Register("ISTIOCTL_AUTHORITY", "", "The istioctl --authority override"),

With a few exceptions, Istio controllers typically are split in two phases: construction and running.

Construction should create informers (via `kclient.New`), setup a queue (via `controllers.NewQueue`), and register event handlers on the informers.
Often, these handlers are adding something to the queue like `client.AddEventHandler(controllers.ObjectHandler(queue.AddObject))`.