StreamingResponseBody with ZipOutputStream to WebFlux and reactive programming

Question

In my application (Spring MVC) I have a legacy endpoint returning a ResponseEntity<StreamingResponseBody>. The StreamingResponseBody is basically a ZipOutputStream built by fetching a list of documents in a S3 storage.

Omitting some parts, the code is as below:

@GetMapping(value = "/zip", produces = MediaType.APPLICATION_OCTET_STREAM_VALUE)
ResponseEntity<StreamingResponseBody> downloadZip() {
    List<String> keys = getMyKeys();

    StreamingResponseBody streamRespBody = outputStream -> {
        try {
            // In getZipOutputStream() each document is fetched from S3 directly into the
            // outputStream (connected to the client browser through 
            // the StreamingResponseBody) so we don't put everything in memory
            this.documentService.getZipOutputStream(outputStream, keys);
        } catch (S3Exception e) {
            throw new RuntimeException(e);
        }
    };

    return ResponseEntity.ok()
        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=documents.zip")
        .contentType(MediaType.APPLICATION_OCTET_STREAM)
        .body(streamRespBody);
}

Now I have to write something equivalent using WebFlux. I have looked around various documentations, resources, tutorials... but I can't figure a working example.

Is is possible to build something equivalent possible with WebFlux, streaming a Zip to a client browser ?

For now, I can't even figure if I should return something like a Flux<SomeClasse> or if my endpoint should be a Mono<void> getZip(HttpServerResponse httpResponse) and write the ZipOutputStream to the client through the httpResponse.