docs: private void doOnLongFocus() {
          final List<OnFocusListener> focusListeners;
          synchronized (mFocusListeners) {
              focusListeners = new ArrayList<>(mFocusListeners);
          }
  
          for (OnFocusListener listener : focusListeners) {
              if (listener.onLongFocus(this)) {
                  return;
              }
          }
          onLongFocus();
          final boolean inFollowFocusGroup = isInFollowFocusGroup();
          for (Widget child : getChildren()) {
              if (child.mFocusEnabled
                      && (mChildrenFollowFocus || child.mFollowParentFocus || inFollowFocusGroup)) {
                  child.doOnLongFocus();
              }
          }
      }