Laravel nova custom card problem

I can't get the resourceId in a custom card, at the compute function. Someone would have the trick?

class CountRelationshipsPerUser extends Card
{
    /**
     * The width of the card (1/3, 1/2, or full).
     *
     * @var string
     */
    public $width = '1/3';

    /**
     * @return CountRelationshipsPerUser
     */
    public function withCount()
    {
        $current_user = ????; ///// HERE
        return $this->withMeta([
            'my_count' => MyModel::where('user_id', $current_user)->count(),
        ]);
    }

    /**
     * Get the component name for the element.
     *
     * @return string
     */
    public function component()
    {
        return 'count-relationships-per-user';
    }
}