In V7, you could store additional data in the extended area of an object, such as the below. What is the functional equivalent in v8?
typedef struct {
lv_slider_ext_t slider; //The ancestor slider structure
int8_t index;
lv_obj_t * leftLabel;
lv_obj_t * label;
} temp_slider_ext_t;
lv_obj_allocate_ext_attr(slider, sizeof(temp_slider_ext_t)); //Re-alloacte the extended data
temp_slider_ext_t * extSlider = (temp_slider_ext_t *)lv_obj_get_ext_attr(slider);
extSlider->label = lblSlrRightValue;