public final int getSectionItemsTotal() {
        int contentItemsTotal;

        switch (state) {
            case LOADED:
                contentItemsTotal = getContentItemsTotal();
                break;
            case LOADING:
            case FAILED:
            case EMPTY:
                contentItemsTotal = 1;
                break;
            default:
                throw new IllegalStateException("Invalid state");
        }

        return contentItemsTotal + (hasHeader ? 1 : 0) + (hasFooter ? 1 : 0);
    }
Return the total of items of this Section, including content items (according to the section
state) plus header and footer.

@return total of items of this section
library/src/main/java/io/github/luizgrp/sectionedrecyclerviewadapter/Section.java