class CoordinatorLayout extends ViewGroup implements NestedScrollingParent2 {

    @Override
    public void setVisibility(int visibility) {
        super.setVisibility(visibility);

        final boolean visible = visibility == VISIBLE;
        if (mStatusBarBackground != null && mStatusBarBackground.isVisible() != visible) {
            mStatusBarBackground.setVisible(visible, false);
        }
    }

    public  CoordinatorLayout(@NonNull Context context);
    public  CoordinatorLayout(@NonNull Context context, @Nullable AttributeSet attrs);
    public  CoordinatorLayout(@NonNull Context context, @Nullable AttributeSet attrs,
            @AttrRes int defStyleAttr);

}