code: func (engine *DockerStatsEngine) handleDockerEvents(events ...interface{}) error {
  	for _, event := range events {
  		dockerContainerChangeEvent, ok := event.(dockerapi.DockerContainerChangeEvent)
  		if !ok {
  			return fmt.Errorf("Unexpected event received, expected docker container change event")
  		}
  
  		switch dockerContainerChangeEvent.Status {
  		case apicontainerstatus.ContainerRunning:
  			engine.addAndStartStatsContainer(dockerContainerChangeEvent.DockerID)
  		case apicontainerstatus.ContainerStopped:
  			engine.removeContainer(dockerContainerChangeEvent.DockerID)
  		default:
  			seelog.Debugf("Ignoring event for container, id: %s, status: %d", dockerContainerChangeEvent.DockerID, dockerContainerChangeEvent.Status)
  		}
  	}
  
  	return nil
  }
docs: // handleDockerEvents must be called after openEventstream; it processes each
  // event that it reads from the docker event stream.