WebSockets Next: CloseReason - fix NPE if connection terminated abruptly

- fix invocation of OnClose callback with a CloseReason param
- resolves quarkusio#42271

extensions/websockets-next/runtime/src/main/java/io/quarkus/websockets/next/CloseReason.java

@@ -50,4 +50,9 @@ public String getMessage() {
         return message;
     }
 
+    @Override
+    public String toString() {
+        return "CloseReason [code=" + code + ", " + (message != null ? "message=" + message : "") + "]";
+    }
+
 }

extensions/websockets-next/runtime/src/main/java/io/quarkus/websockets/next/runtime/WebSocketConnectionBase.java

@@ -131,7 +131,12 @@ public BroadcastSender broadcast() {
     public CloseReason closeReason() {
         WebSocketBase ws = webSocket();
         if (ws.isClosed()) {
-            return new CloseReason(ws.closeStatusCode(), ws.closeReason());
+            Short code = ws.closeStatusCode();
+            if (code == null) {
+                // This could happen if the connection is terminated abruptly
+                return CloseReason.INTERNAL_SERVER_ERROR;
+            }
+            return new CloseReason(code, ws.closeReason());
         }
         return null;
     }