code: func (ctx *Context) SaveToFile(name, savePath string) error {
  	fr, _, err := ctx.GetFile(name)
  	if err != nil {
  		return err
  	}
  	defer fr.Close()
  
  	fw, err := os.OpenFile(savePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
  	if err != nil {
  		return err
  	}
  	defer fw.Close()
  
  	_, err = io.Copy(fw, fr)
  	return err
  }
docs: // SaveToFile reads a file from request by field name and saves to given path.