interfaceRxBytes  MetricName = "rx_bytes"
	interfaceRxErrors MetricName = "rx_errors"
	interfaceTxBytes  MetricName = "tx_bytes"
	interfaceTxErrors MetricName = "tx_errors"

	// cpu stats
	cpuUser       MetricName = "user"
	cpuSystem     MetricName = "system"
	cpuIOWait     MetricName = "iowait"
	cpuIdle       MetricName = "idle"
	cpuNice       MetricName = "nice"
	cpuSteal      MetricName = "steal"
	cpuLoad1      MetricName = "load1"

// value of this type is passed to the `MetricsLoaderFn`.
type MetricValues struct {
	values      map[MetricName][]metricValue
	descriptors map[MetricName]MetricDescriptor
}

func newMetricValues(d map[MetricName]MetricDescriptor) MetricValues {
	return MetricValues{
		values:      make(map[MetricName][]metricValue, len(d)),
		descriptors: d,
	}
}

type ObjectMetricSource struct {
	// target is the described Kubernetes object.
	Target CrossVersionObjectReference `json:"target" protobuf:"bytes,1,name=target"`

	// metricName is the name of the metric in question.
	MetricName string `json:"metricName" protobuf:"bytes,2,name=metricName"`
	// targetValue is the target value of the metric (as a quantity).
	TargetValue resource.Quantity `json:"targetValue" protobuf:"bytes,3,name=targetValue"`

type ObjectMetricSource struct {
	// target is the described Kubernetes object.
	Target CrossVersionObjectReference `json:"target" protobuf:"bytes,1,name=target"`

	// metricName is the name of the metric in question.
	MetricName string `json:"metricName" protobuf:"bytes,2,name=metricName"`

	// targetValue is the target value of the metric (as a quantity).
	TargetValue resource.Quantity `json:"targetValue" protobuf:"bytes,3,name=targetValue"`

// messaging service, or QPS from loadbalancer running outside of cluster).
// Exactly one "target" type should be set.
message ExternalMetricSource {
  // metricName is the name of the metric in question.
  optional string metricName = 1;

  // metricSelector is used to identify a specific time series
  // within a given metric.
  // +optional

	metrics, timestamp, err := c.metricsClient.GetRawMetric(metricName, namespace, selector, metricSelector)
	if err != nil {
		return 0, 0, time.Time{}, fmt.Errorf("unable to get metric %s: %v", metricName, err)
	}

// any Kubernetes object (for example length of queue in cloud
// messaging service, or QPS from loadbalancer running outside of cluster).
message ExternalMetricSource {
  // metricName is the name of the metric in question.
  optional string metricName = 1;

  // metricSelector is used to identify a specific time series
  // within a given metric.
  // +optional

// any Kubernetes object (for example length of queue in cloud
// messaging service, or QPS from loadbalancer running outside of cluster).
message ExternalMetricSource {
  // metricName is the name of the metric in question.
  optional string metricName = 1;

  // metricSelector is used to identify a specific time series
  // within a given metric.
  // +optional

// messaging service, or QPS from loadbalancer running outside of cluster).
// Exactly one "target" type should be set.
message ExternalMetricSource {
  // metricName is the name of the metric in question.
  optional string metricName = 1;

  // metricSelector is used to identify a specific time series
  // within a given metric.
  // +optional

	return
}

// MarshalMsg implements msgp.Marshaler
func (z MetricName) MarshalMsg(b []byte) (o []byte, err error) {
	o = msgp.Require(b, z.Msgsize())
	o = msgp.AppendString(o, string(z))
	return
}

// UnmarshalMsg implements msgp.Unmarshaler
func (z *MetricName) UnmarshalMsg(bts []byte) (o []byte, err error) {
	{
		var zb0001 string