protected boolean originIndicatesRetryableInternalServerError(HttpResponse response) {
        // override for custom origin headers for retry
        return false;
    }
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