sort_container_metrics.go
func SortContainerMetrics(messages []*events.ContainerMetric) []*events.ContainerMetric {
	sort.Sort(containerMetricSlice(messages))
	return messages
}
func SortContainerMetrics(messages []*events.ContainerMetric) []*events.ContainerMetric {
	sort.Sort(containerMetricSlice(messages))
	return messages
}
// SortContainerMetrics sorts a slice of containerMetrics by InstanceIndex.
//
// The input slice is sorted; the return value is simply a pointer to the same slice.