docs: public void setViewClass(final Class<? extends ThymeleafReactiveView> viewClass) {
          if (viewClass == null || !ThymeleafReactiveView.class.isAssignableFrom(viewClass)) {
              throw new IllegalArgumentException(
                      "Given view class [" + (viewClass != null ? viewClass.getName() : null) +
                      "] is not of type [" + ThymeleafReactiveView.class.getName() + "]");
          }
          this.viewClass = viewClass;
      }