public function handle($message, callable $next)
 {
     $messageSubscribers = $this->messageSubscribersResolver->resolve($message);
     foreach ($messageSubscribers as $messageSubscriber) {
         call_user_func($messageSubscriber, $message);
     }
     $next($message);
 }
 public function handle($message, callable $next)
 {
     $messageSubscribers = $this->messageSubscribersResolver->resolve($message);
     foreach ($messageSubscribers as $messageSubscriber) {
         $this->logger->log($this->level, 'Started notifying a subscriber', ['subscriber' => $messageSubscriber]);
         call_user_func($messageSubscriber, $message);
         $this->logger->log($this->level, 'Finished notifying a subscriber', ['subscriber' => $messageSubscriber]);
     }
     $next($message);
 }