Laravel Mqtt's subscription doesn't end - laravel

Question

I receive an Mqtt message from Laravel and try to do some action, but if you subscribe, you only get one message and it takes about a minute to delay.
I referred to this at https://github.com/salmanzafar949/MQTT-Laravel.
Implementing Mqtttt motion was made by creating a separate controller.
My code is
<?php
namespace App\Http\Controllers;
use Salman\Mqtt\MqttClass\Mqtt;
use Illuminate\Http\Request;
class MqttController extends Controller{
public $token = "";
public function SendMsgViaMqtt(Request $request)
{
$mqtt = new Mqtt();
//$client_id = Auth::user()->id;/
$topic = $request->topic;
$token = $request->token;
$message = $request->message;
$output = $mqtt->ConnectAndPublish("test", $message, "");
if ($output === true)
{
if($token == "none" || !$token){
return "End";
}else{
$this->SubscribetoTopic($token);
}
}else{
return "Failed";
}
}
public function SubscribetoTopic($token)
{
$topic = 'test';
$this->token = $token;
$message = [];
$mqtt = new Mqtt();
$client_id = "";
$mqtt->ConnectAndSubscribe($topic, function($topic, $msg){
if($msg == "end"){
$message = [
'title' => '魚が釣れました',
'body' => '釣竿を確認してください',
'click_action' => 'Url'
];
}else if($msg == "no"){
$message = [
'title' => '測定できません',
'body' => '波が強すぎると測れません',
'click_action' => 'Url'
];
}else{
return "end";
}
return $this->sendCrul($this->token, $message);
}, "");
}
public function sendCrul($token, $message){
define('SERVER_API_KEY', 'APIKEY');
$tokens = $token;
$header = [
'Authorization: Key=' . SERVER_API_KEY,
'Content-Type: Application/json'
];
$payload = [
'to' => $tokens,
'notification' => $message
];
$curl = curl_init();
curl_setopt_array($curl, array(
CURLOPT_URL => "https://fcm.googleapis.com/fcm/send",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => json_encode( $payload ),
CURLOPT_HTTPHEADER => $header
));
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if($err){
echo "cURL Error #:". $err;
}else{
return $response;
}
// return "ok";
}
}
If you're in trouble like me, let me know how.