protected function createUniqueUsername( $username )
    {
        $originalName = $username;
        $existingUser = $this->userManager->findUserByUsername( $username );
        $suffix = 0;
        while ( $existingUser )
        {
            $suffix++;
            $username = $originalName . $suffix;
            $existingUser = $this->userManager->findUserByUsername( $username );
        }
        return $username;
    }