Update data-plane/receiver/src/main/java/dev/knative/eventing/kafka/b…

…roker/receiver/impl/auth/OIDCDiscoveryConfigListener.java

Co-authored-by: Pierangelo Di Pilato <[email protected]>

data-plane/receiver/src/main/java/dev/knative/eventing/kafka/broker/receiver/impl/auth/OIDCDiscoveryConfigListener.java

@@ -65,7 +65,7 @@ public OIDCDiscoveryConfig getOidcDiscoveryConfig() {
         return oidcDiscoveryConfig.get();
     }
 
-    public int registerCallback(Consumer<OIDCDiscoveryConfig> callback) {
+    public synchronized int registerCallback(Consumer<OIDCDiscoveryConfig> callback) {
         this.callbacks.add(callback);
         return this.callbacks.size() - 1;
     }