code: func PodContainerKey(namespace, podName, containerName string) string {
  	return fmt.Sprintf("namespace:%s/pod:%s/container:%s", namespace, podName, containerName)
  }
docs: // MetricsSet keys are inside of DataBatch. The structure of the returned string is
  // an implementation detail and no component should rely on it as it may change
  // anytime. It only guaranteed that it is unique for the unique combination of
  // passed parameters.