code: func (engine *DockerStatsEngine) stopTrackingContainerUnsafe(container *StatsContainer, taskARN string) bool {
  	terminal, err := container.terminal()
  	if err != nil {
  		// Error determining if the container is terminal. This means that the container
  		// id could not be resolved to a container that is being tracked by the
  		// docker task engine. If the docker task engine has already removed
  		// the container from its state, there's no point in stats engine tracking the
  		// container. So, clean-up anyway.
  		seelog.Warnf("Error determining if the container %s is terminal, removing from stats, err: %v", container.containerMetadata.DockerID, err)
  		engine.doRemoveContainerUnsafe(container, taskARN)
  		return true
  	}
  	if terminal {
  		// Container is in known terminal state. Stop collection metrics.
  		seelog.Infof("Container %s is terminal, removing from stats", container.containerMetadata.DockerID)
  		engine.doRemoveContainerUnsafe(container, taskARN)
  		return true
  	}
  
  	return false
  }
docs: // stopTrackingContainerUnsafe removes the StatsContainer from stats engine and
  // returns true if the container is stopped or no longer tracked in agent. Otherwise
  // it does nothing and return false