code: func layerStatusFromDockerString(dockerStatus string) layerStatus {
  	switch dockerStatus {
  	case "Pushing":
  		return statusPushing
  	case "Downloading":
  		return statusDownloading
  	case "Extracting", "Verifying Checksum", "Download complete":
  		return statusExtracting
  	case "Pull complete", "Already exists", "Pushed", "Layer already exists":
  		return statusComplete
  	default:
  		return statusPending
  	}
  }
docs: // layerStatusFromDockerString translates a string in a Docker status
  // line to a layerStatus