private static void render(OutputStream out, TestReport report) throws IOException {
        JsonGenerator json = factory.createGenerator(out);
        json.writeStartObject();

        json.writeFieldName("report");
        render(json, (Node) report.root());

        json.writeEndObject();
        json.close();
    }
@author valerijf
@author jonmv
@author mortent
vespa-osgi-testrunner/src/main/java/com/yahoo/vespa/testrunner/TestRunnerHandler.java