code: func (b *Bundle) EnsureLoaded(c context.Context) error {
  	// Always reload in debug mode. Load only once in non-debug mode.
  	if dm := b.DebugMode; dm != nil && dm(c) {
  		b.templates, b.err = b.Loader(c, b.FuncMap)
  	} else {
  		b.once.Do(func() {
  			b.templates, b.err = b.Loader(c, b.FuncMap)
  		})
  	}
  	return b.err
  }
docs: // EnsureLoaded loads all the templates if they haven't been loaded yet.