public boolean isSectionItemSelected(int sectionIndex, int itemIndex) {
        SectionSelectionState state = getSectionSelectionState(sectionIndex);
        return state.section || state.items.get(itemIndex);
    }
Check whether a specific item in a section is selected, or if the entire section is selected

@param sectionIndex index of section
@param itemIndex    index of item in section
@return true if the item is selected
android/modules/module_common/src/main/java/github/tornaco/android/thanos/widget/section/SectioningAdapter.java