// rememberLayersOfManifest caches the layer digests of given manifest
func (r *repository) rememberLayersOfManifest(manifestDigest digest.Digest, manifest distribution.Manifest, cacheName string) {
	r.cachedLayers.RememberDigest(manifestDigest, r.blobrepositorycachettl, cacheName)

	// remember the layers in the cache as an optimization to avoid searching all remote repositories
	for _, layer := range manifest.References() {
		r.cachedLayers.RememberDigest(layer.Digest, r.blobrepositorycachettl, cacheName)
	}
}
// rememberLayers caches the provided layers
func (r *repository) rememberLayers(manifest distribution.Manifest, cacheName string) {
	if !r.pullthrough {
		return
	}
	// remember the layers in the cache as an optimization to avoid searching all remote repositories
	for _, layer := range manifest.References() {
		r.cachedLayers.RememberDigest(layer.Digest, cacheName)
	}
}