src/Knp/Menu/Util/MenuManipulator.php
public function split(ItemInterface $item, $length)
    {
        return array(
            'primary' => $this->slice($item, 0, $length),
            'secondary' => $this->slice($item, $length),
        );
    }
public function split(ItemInterface $item, $length)
    {
        return array(
            'primary' => $this->slice($item, 0, $length),
            'secondary' => $this->slice($item, $length),
        );
    }
Split menu into two distinct menus.

@param ItemInterface $item
@param mixed         $length Name of child, child object, or numeric length.

@return array Array with two menus, with "primary" and "secondary" key