private static void addExecutorService(Mode mode, Element rootElement, Document doc,
                                           TikaConfig config) {
        ExecutorService executor = config.getExecutorService();

        // TODO Implement the reverse of ExecutorServiceXmlLoader
        // TODO Make it possible to detect if we have the default executor
        // TODO Make it possible to get the current values from ConfigurableThreadPoolExecutor
    }
@param config  config to serialize
@param mode    serialization mode
@param writer  writer
@param charset charset
@throws Exception
tika-core/src/main/java/org/apache/tika/config/TikaConfigSerializer.java