I need to invoke remote HTTP endpoint with an WebClient.

Due to the absence of the DTO classes, I need to send/receive request/response as instances of ObjectNode.

I have no problem with Jackson, yet I'm not sure which method should I use regarding request/response body.

    Mono<ObjectNode> invoke() {
    WebClient webClient = webClient();    // ok 
    ObjectNo requestNode = requestNode(); // ok

    webClient.post()                      // ok
             .uri(b -> b.build())         // ok
             .body(...........)           // how?
             .exchangeToMono(r -> {       // how?
    });
}