func ImportLayer(path string, importFolderPath string, parentLayerPaths []string) error {
	title := "hcsshim::ImportLayer "
	logrus.Debugf(title+"path %s folder %s", path, importFolderPath)
	layers, err := layerPathsToDescriptors(parentLayerPaths)
	if err != nil {
		return err
	}
	err = importLayer(&stdDriverInfo, path, importFolderPath, layers)
	if err != nil {
		err = hcserror.Errorf(err, title, "path=%s folder=%s", path, importFolderPath)
		logrus.Error(err)
		return err
	}
	logrus.Debugf(title+"succeeded path=%s folder=%s", path, importFolderPath)
	return nil
}
ImportLayer will take the contents of the folder at importFolderPath and import
that into a layer with the id layerId.  Note that in order to correctly populate
the layer and interperet the transport format, all parent layers must already
be present on the system at the paths provided in parentLayerPaths.
package wclayer
import (
	"errors"
	"io/ioutil"
	"os"
	"path/filepath"
	"github.com/Microsoft/go-winio"
	"github.com/Microsoft/hcsshim/internal/hcserror"
	"github.com/Microsoft/hcsshim/internal/safefile"
	"github.com/sirupsen/logrus"
)