code: protected final boolean callbackPrepareOptionsMenu(Menu menu) {
          if (DEBUG) Log.d(TAG, "[callbackPrepareOptionsMenu] menu: " + menu);
  
          boolean result = true;
          if (mActivity instanceof OnPreparePanelListener) {
              OnPreparePanelListener listener = (OnPreparePanelListener)mActivity;
              result = listener.onPreparePanel(Window.FEATURE_OPTIONS_PANEL, null, menu);
          } else if (mActivity instanceof OnPrepareOptionsMenuListener) {
              OnPrepareOptionsMenuListener listener = (OnPrepareOptionsMenuListener)mActivity;
              result = listener.onPrepareOptionsMenu(menu);
          }
  
          if (DEBUG) Log.d(TAG, "[callbackPrepareOptionsMenu] returning " + result);
          return result;
      }
docs: Internal method to trigger the menu preparation process.
  
  @return {@code true} if menu preparation should proceed.