actionMessage.php

    // di file SiteController.php

    public function actionMessage()
    {
        $sse = new \app\components\SSE();
        $counter = rand(1, 10);
        $t = time();

        //$sse->retry(3000);
        while ((time() - $t) < 15) {
            // Every second, sent a "ping" event.

            $curDate = date(DATE_ISO8601);
            $sse->event('ping',['time' => $curDate]);

            // Send a simple message at random intervals.

            $counter--;
            if (!$counter) {
                $sse->message("This is a message at time $curDate");
                $counter = rand(1, 10);
            }

            $sse->flush();
            sleep(1);
        }
        exit();
    }