private static int examineExecutor(Executor executor) {
        if (executor instanceof ThreadPoolExecutor) {
            return ((ThreadPoolExecutor) executor).getMaximumPoolSize();
        }
        return Integer.MAX_VALUE; // assume unbound
    }
If present, responses from this will set the HTTP response header with this key to the host name of this
container-search/src/main/java/com/yahoo/search/handler/SearchHandler.java