@VisibleForTesting
    void stripXFFHeaders(HttpRequest req) {
        HttpHeaders headers = req.headers();
        for (AsciiString headerName : HEADERS_TO_STRIP) {
            headers.remove(headerName);
        }
    }
Strip out any X-Forwarded-* headers from inbound http requests if connection is not trusted.
zuul-core/src/main/java/com/netflix/netty/common/proxyprotocol/StripUntrustedProxyHeadersHandler.java