@Override
    public void render(OutputStream outputStream) throws IOException {
        try (clientResponse) {
            if (clientResponse.getEntity() != null)
                clientResponse.getEntity().writeTo(outputStream);
        }
    }
Proxies response back to client, keeps Content-Type header if it is present

@author olaa
@author freva
configserver/src/main/java/com/yahoo/vespa/config/server/http/ProxyResponse.java