src/Auth/Auth.php
public function setUserId($userId) {
        $this->userId = $userId;
        if ($this->session !== null) {
            $this->session->set('userId', $userId);
        }
    }
public function setUserId($userId) {
        $this->userId = $userId;
        if ($this->session !== null) {
            $this->session->set('userId', $userId);
        }
    }
Set the user id.

@param int $userId