Use event extender where possible

filter extender will eliminate the last callback-style extender before stable.

extensions/sticky/extend.php

@@ -9,8 +9,12 @@
 
 use Flarum\Api\Controller\ListDiscussionsController;
 use Flarum\Api\Serializer\DiscussionSerializer;
+use Flarum\Discussion\Event\Saving;
 use Flarum\Extend;
+use Flarum\Sticky\Event\DiscussionWasStickied;
+use Flarum\Sticky\Event\DiscussionWasUnstickied;
 use Flarum\Sticky\Listener;
+use Flarum\Sticky\Listener\SaveStickyToDatabase;
 use Flarum\Sticky\Post\DiscussionStickiedPost;
 use Illuminate\Contracts\Events\Dispatcher;
 
@@ -38,9 +42,13 @@ return [
 
     new Extend\Locales(__DIR__.'/locale'),
 
+    (new Extend\Event())
+        ->listen(Saving::class, SaveStickyToDatabase::class)
+        ->listen(DiscussionWasStickied::class, [Listener\CreatePostWhenDiscussionIsStickied::class, 'whenDiscussionWasStickied'])
+        ->listen(DiscussionWasUnstickied::class, [Listener\CreatePostWhenDiscussionIsStickied::class, 'whenDiscussionWasUnstickied']),
+
     function (Dispatcher $events) {
-        $events->subscribe(Listener\CreatePostWhenDiscussionIsStickied::class);
+        // Replace with Filter extender before stable
         $events->subscribe(Listener\PinStickiedDiscussionsToTop::class);
-        $events->subscribe(Listener\SaveStickyToDatabase::class);
     },
 ];