fun getModel(id: Int: CompletableFuture<Model> {
        val request: HttpRequest = //...
        return sendAsync(request)
    }

protected inline fun <reified T> sendAsync(
        request: HttpRequest,
        typeReference: TypeReference<T> = jacksonTypeRef()
    ): CompletableFuture<T> {
        return client.sendAsync(request) { _ ->
            BodySubscribers.mapping(BodySubscribers.ofString(StandardCharsets.UTF_8)) {
                mapper.readValue(it, typeReference)
            }
        }.thenApply { it.body() }
    }

reified T

TypeReference