Second parameter of count function doesn't affect Countable

Code
<?php

/**
 * Just added as comment to php documentation
 * http://us3.php.net/manual/en/countable.count.php
 */
class Foo implements Countable
{
    public function 
count()
    {
        
var_dump(func_get_args());
        return 
1;
    }
}

// recursive parameter doesn't affect Countable
echo count(new Foo(), COUNT_RECURSIVE);
Result
array(0) {
}
1
Used Versions
PHP 7.1, Zend 3.0, Symfony 3.2, Laravel 5.2, PHPUnit 5.6, Doctrine 2.6