src/Leevel/Http/Bag.php
protected function parseFilterId($filter): int
    {
        $filter = $this->isInt($filter) ? $filter : filter_id($filter);

        return $filter;
    }
protected function parseFilterId($filter): int
    {
        $filter = $this->isInt($filter) ? $filter : filter_id($filter);

        return $filter;
    }
分析转换 filter_var 参数.

@param mixed $filter

@return int