code: func (fs *FileStore) Close() error {
  	fs.Lock()
  	if fs.closed {
  		fs.Unlock()
  		return nil
  	}
  	fs.closed = true
  
  	err := fs.genericStore.close()
  
  	fm := fs.fm
  	lockFile := fs.lockFile
  	fs.Unlock()
  
  	if fm != nil {
  		if fmerr := fm.close(); fmerr != nil && err == nil {
  			err = fmerr
  		}
  	}
  	if lockFile != nil {
  		err = util.CloseFile(err, lockFile)
  	}
  	return err
  }
docs: // Close closes all stores.