private void processResponseFromOrigin(HttpResponse originResponse) {
        if (originResponse.status().code() >= 500) {
            handleOriginNonSuccessResponse(originResponse, chosenServer.get());
        } else {
            handleOriginSuccessResponse(originResponse, chosenServer.get());
        }
    }
Request is replayable on a different origin IFF
A) we have not started to send response back to the client  AND
B) we have not lost any of its body chunks
zuul-core/src/main/java/com/netflix/zuul/filters/endpoint/ProxyEndpoint.java