public function total(array $args = []): int
    {
        // Establish args.

        $default_args = [
            // Also used by {@link all()}.
            'taxonomy_filters'   => [],
            'taxonomies_include' => [],
            'taxonomies_exclude' => [],
            'filters'            => [
                'get'        => 'all',
                'hide_empty' => false,
                'orderby'    => 'name',
            ],
            'no_cache' => false,
        ];
        $args = array_merge($default_args, $args);
        $args = array_intersect_key($args, $default_args);

        $args['taxonomy_filters']   = (array) $args['taxonomy_filters'];
        $args['taxonomies_include'] = (array) $args['taxonomies_include'];
        $args['taxonomies_exclude'] = (array) $args['taxonomies_exclude'];
        $args['filters']            = (array) $args['filters'];
        $args['no_cache']           = (bool) $args['no_cache'];

        // Check cache; already did this query?

        $cache_keys = $args; // Keys to consider when checking the cache.
        unset($cache_keys['no_cache']); // Cache key exclusions.

        if (($total = &$this->cacheKey(__FUNCTION__, $cache_keys)) !== null && !$args['no_cache']) {
            return $total; // Already cached this.
        }
        // Establish total terms in the query.

        $taxonomies = get_taxonomies($args['taxonomy_filters'], 'objects');
        $taxonomies = $args['taxonomies_include'] ? array_intersect_key($taxonomies, array_fill_keys($args['taxonomies_include'], true)) : $taxonomies;
        $taxonomies = $args['taxonomies_exclude'] ? array_diff_key($taxonomies, array_fill_keys($args['taxonomies_exclude'], true)) : $taxonomies;

        $terms = get_terms(array_merge(['taxonomy' => array_keys($taxonomies)], $args['filters'], ['fields' => 'all']));
        $terms = is_array($terms) ? $terms : []; // Force array.

        return $total = count($terms);
    }