code: func (reg *registry) Enumerate(ctx context.Context, ingester func(string) error) error {
  	root, err := pathFor(repositoriesRootPathSpec{})
  	if err != nil {
  		return err
  	}
  
  	err = reg.blobStore.driver.Walk(ctx, root, func(fileInfo driver.FileInfo) error {
  		return handleRepository(fileInfo, root, "", ingester)
  	})
  
  	return err
  }
docs: // Enumerate applies ingester to each repository