Add an invokable resolve connection message class so that we don't need to a closure in the config file that we can't properly cache

app/Http/Controllers/ControlMessageController.php

@@ -154,7 +154,14 @@ protected function resolveConnectionMessage($connectionInfo, $user)
     {
         $deferred = new Deferred();
 
-        $connectionMessageResolver = config('expose-server.messages.resolve_connection_message')($connectionInfo, $user);
+        $resolveConnectionMessage = config('expose-server.messages.resolve_connection_message');
+        if(is_string($resolveConnectionMessage) && class_exists($resolveConnectionMessage)) {
+            $connectionMessageResolver = (new $resolveConnectionMessage())($connectionInfo, $user);
+        } else if($resolveConnectionMessage instanceof \Closure) {
+            $connectionMessageResolver = $resolveConnectionMessage($connectionInfo, $user);
+        } else {
+            $connectionMessageResolver = $resolveConnectionMessage;
+        }
 
         if ($connectionMessageResolver instanceof PromiseInterface) {
             $connectionMessageResolver->then(function ($connectionMessage) use ($connectionInfo, $deferred) {

app/Support/Messages/ResolveConnectionMessage.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Expose\Server\Support\Messages;
+
+use Expose\Server\Connections\ControlConnection;
+
+class ResolveConnectionMessage
+{
+    public function __invoke(ControlConnection $connectionInfo, array|null $user)
+    {
+        return config('expose-server.messages.message_of_the_day');
+    }
+}

config/expose-server.php

@@ -165,9 +165,7 @@
     |
     */
     'messages' => [
-        'resolve_connection_message' => function ($connectionInfo, $user) {
-            return config('expose-server.messages.message_of_the_day');
-        },
+        'resolve_connection_message' => \Expose\Server\Support\Messages\ResolveConnectionMessage::class,
 
         'message_of_the_day' => 'Thank you for using expose.',