Publish a message to GCP Pub/Sub Topic

publishmessage.java

public Mono<Void> publish(Message message) {
    ByteString data = ByteString.copyFromUtf8(JsonUtils.writeValueAsString(message, objectMapper));
    PubsubMessage pubSubMessage = PubsubMessage.newBuilder().setData(data).build();
    ApiFuture<String> messageIdFuture = publisher.publish(pubSubMessage);
    Mono<String> messageIdMono = ApiFutureUtil.toMono(messageIdFuture);
    return messageIdMono.then();
}