code: func (t *BinaryLoader) Binary(assetFn func(name string) ([]byte, error), namesFn func() []string) {
  	if assetFn == nil || namesFn == nil {
  		return
  	}
  
  	t.AssetFn = assetFn
  	t.NamesFn = namesFn
  	// if extension is not static(setted by .Directory)
  	if t.Extension == "" {
  		if names := namesFn(); len(names) > 0 {
  			t.Extension = filepath.Ext(names[0]) // we need the extension to get the correct template engine on the Render method
  		}
  	}
  }
docs: // Binary optionally, called after Loader.Directory, used when files are distributed inside the app executable
  // sets the AssetFn and NamesFn