agent/stats/engine.go
func (engine *DockerStatsEngine) ContainerDockerStats(taskARN string, containerID string) (*types.StatsJSON, error) {
	engine.lock.RLock()
	defer engine.lock.RUnlock()

	containerIDToStatsContainer, ok := engine.tasksToContainers[taskARN]
	if !ok {
		return nil, errors.Errorf("stats engine: task '%s' for container '%s' not found",
			taskARN, containerID)
	}

	container, ok := containerIDToStatsContainer[containerID]
	if !ok {
		return nil, errors.Errorf("stats engine: container not found: %s", containerID)
	}
	return container.statsQueue.GetLastStat(), nil

}
func (engine *DockerStatsEngine) ContainerDockerStats(taskARN string, containerID string) (*types.StatsJSON, error) {
	engine.lock.RLock()
	defer engine.lock.RUnlock()

	containerIDToStatsContainer, ok := engine.tasksToContainers[taskARN]
	if !ok {
		return nil, errors.Errorf("stats engine: task '%s' for container '%s' not found",
			taskARN, containerID)
	}

	container, ok := containerIDToStatsContainer[containerID]
	if !ok {
		return nil, errors.Errorf("stats engine: container not found: %s", containerID)
	}
	return container.statsQueue.GetLastStat(), nil

}
// ContainerDockerStats returns the last stored raw docker stats object for a container