agent/stats/engine.go
func newMetricsMetadata(cluster *string, containerInstance *string) *ecstcs.MetricsMetadata {
	return &ecstcs.MetricsMetadata{
		Cluster:           cluster,
		ContainerInstance: containerInstance,
	}
}
func newMetricsMetadata(cluster *string, containerInstance *string) *ecstcs.MetricsMetadata {
	return &ecstcs.MetricsMetadata{
		Cluster:           cluster,
		ContainerInstance: containerInstance,
	}
}
// newMetricsMetadata creates the singleton metadata object.