docs: public synchronized MessageRouterConfigListenerImpl register(BundleContext bundleContext) {
          if (serviceRegistration != null) {
              return this; // Already registered.
          }
  
          Dictionary<String, Object> props = new Hashtable<String, Object>(1);
          props.put(Constants.SERVICE_VENDOR, "IBM");
  
          // register the ManagedService that will handle the config
          serviceRegistration = bundleContext.registerService(MessageRouterConfigListener.class, this, props);
          return this;
      }