private JsonGenerator createJsonGenerator(OutputStream outputStream) throws IOException {
        return generatorFactory.createGenerator(outputStream, JsonEncoding.UTF8)
                .configure(JsonGenerator.Feature.AUTO_CLOSE_TARGET, false)
                .configure(JsonGenerator.Feature.FLUSH_PASSED_TO_STREAM, false);
    }
Formatting of an {@link AccessLogEntry} in the Vespa JSON access log format.

@author frodelu
container-core/src/main/java/com/yahoo/container/logging/JSONFormatter.java