public void forEachField(BiConsumer<String, Json> consumer) {
        requireType(Type.OBJECT);
        inspector.traverse((ObjectTraverser) (name, inspector) -> {
            consumer.accept(name, field(name));
        });
    }
@return true if the JSON field was present but its value was 'null'
vespajlib/src/main/java/ai/vespa/json/Json.java