code: func FileExists(filePath string) (bool, int64, error) {
  	fileInfo, err := os.Stat(filePath)
  	if os.IsNotExist(err) {
  		return false, 0, nil
  	}
  	if err != nil {
  		return false, 0, errors.Wrapf(err, "error checking if file [%s] exists", filePath)
  	}
  	return true, fileInfo.Size(), nil
  }
docs: // FileExists checks whether the given file exists.
  // If the file exists, this method also returns the size of the file.