public function loginAs(int $user_id, bool $remember = false): bool
    {
        if (!$user_id) {
            return false; // Impossible.
        }
        $on_set_auth_cookie = function (string $value) {
            $_COOKIE[is_ssl() ? SECURE_AUTH_COOKIE : AUTH_COOKIE] = $value;
        };
        $on_set_logged_in_cookie = function (string $value) {
            $_COOKIE[LOGGED_IN_COOKIE] = $value;
        };
        add_action('set_auth_cookie', $on_set_auth_cookie);
        add_action('set_logged_in_cookie', $on_set_logged_in_cookie);

        wp_clear_auth_cookie();
        wp_set_auth_cookie($user_id, $remember);

        remove_action('set_auth_cookie', $on_set_auth_cookie);
        remove_action('set_logged_in_cookie', $on_set_logged_in_cookie);

        wp_set_current_user(0);
        wp_set_current_user($user_id);

        return (int) get_current_user_id() === $user_id;
    }