code: func NewConfigManifestBuilder(bs distribution.BlobService, pk libtrust.PrivateKey, ref reference.Named, configJSON []byte) distribution.ManifestBuilder {
  	return &configManifestBuilder{
  		bs:         bs,
  		pk:         pk,
  		configJSON: configJSON,
  		ref:        ref,
  	}
  }
docs: // NewConfigManifestBuilder is used to build new manifests for the current
  // schema version from an image configuration and a set of descriptors.
  // It takes a BlobService so that it can add an empty tar to the blob store
  // if the resulting manifest needs empty layers.