docs: @Handler(dynamic = true)
      public void onConfigurationUpdate(ConfigurationUpdate event)
              throws BackingStoreException {
          if (event instanceof InitialPreferences) {
              return;
          }
          for (String path : event.paths()) {
              Optional<Map<String, String>> prefs = event.values(path);
              path = path.substring(1); // Remove leading slash
              if (!prefs.isPresent()) {
                  preferences.node(path).removeNode();
                  continue;
              }
              for (Map.Entry<String, String> e : prefs.get().entrySet()) {
                  preferences.node(path).put(e.getKey(), e.getValue());
              }
          }
          preferences.flush();
      }