code: func newDockerContainerMetadataResolver(taskEngine ecsengine.TaskEngine) (*DockerContainerMetadataResolver, error) {
  	dockerTaskEngine, ok := taskEngine.(*ecsengine.DockerTaskEngine)
  	if !ok {
  		// Error type casting docker task engine.
  		return nil, fmt.Errorf("Could not load docker task engine")
  	}
  
  	resolver := &DockerContainerMetadataResolver{
  		dockerTaskEngine: dockerTaskEngine,
  	}
  
  	return resolver, nil
  }
docs: // newDockerContainerMetadataResolver returns a new instance of DockerContainerMetadataResolver.