Changed return type to void for Hyperf\Event\Contract\ListenerInterface::process(). (#4611)

Author: limingxinleo

src/Listener/QueueHandleListener.php

@@ -41,7 +41,7 @@ public function listen(): array
         ];
     }
 
-    public function process(object $event)
+    public function process(object $event): void
     {
         if ($event instanceof Event && $event->getMessage()->job()) {
             $job = $event->getMessage()->job();

src/Listener/QueueLengthListener.php

@@ -37,7 +37,7 @@ public function listen(): array
     /**
      * @param QueueLength $event
      */
-    public function process(object $event)
+    public function process(object $event): void
     {
         $value = 0;
         foreach ($this->level as $level => $value) {

src/Listener/ReloadChannelListener.php

@@ -38,7 +38,7 @@ public function listen(): array
     /**
      * @param QueueLength $event
      */
-    public function process(object $event)
+    public function process(object $event): void
     {
         if (! $event instanceof QueueLength) {
             return;