code: func (f *Field) Close() error {
  	f.mu.Lock()
  	defer f.mu.Unlock()
  
  	// Close the attribute store.
  	if f.rowAttrStore != nil {
  		_ = f.rowAttrStore.Close()
  	}
  
  	// Close all views.
  	for _, view := range f.viewMap {
  		if err := view.close(); err != nil {
  			return err
  		}
  	}
  	f.viewMap = make(map[string]*view)
  
  	return nil
  }
docs: // Close closes the field and its views.