public JettyServiceBuilder insertHandler(Handler.Singleton handler) {
        handlerWrappers.add(requireNonNull(handler, "handler"));
        return this;
    }
Adds the specified {@link Handler.Wrapper} to the Jetty {@link Server}.

@see Server#insertHandler(Singleton)
jetty/jetty12/src/main/java/com/linecorp/armeria/server/jetty/JettyServiceBuilder.java