code: public ServerBuilder service(PathMapping pathMapping, Service<HttpRequest, HttpResponse> service) {
          defaultVirtualHostBuilderUpdated();
          defaultVirtualHostBuilder.service(pathMapping, service);
          return this;
      }
docs: Binds the specified {@link Service} at the specified {@link PathMapping} of the default
  {@link VirtualHost}.
  
  @throws IllegalStateException if the default {@link VirtualHost} has been set via
  {@link #defaultVirtualHost(VirtualHost)} already