preload for little vGL

void preload_demo(void)
{
    static lv_style_t style;
    lv_style_copy(&style, &lv_style_plain);
    style.line.width = 10;
    style.line.color = lv_color_hex3(0x258);

    style.body.border.color = lv_color_hex3(0xbbb);
    style.body.border.width = 10;
    style.body.padding.left = 0;

    /*Create a preloader object*/
    lv_obj_t* preload = lv_preload_create(lv_scr_act(), NULL);
    lv_obj_set_size(preload, 100, 100);
    lv_obj_align(preload, NULL, LV_ALIGN_CENTER, 0, 0);
    lv_preload_set_style(preload,LV_PRELOAD_STYLE_MAIN, &style);
}