private static byte[] downloadURL(URL url, String postData)
throws Exception {
ResourceDownloaderFactory rdf = StaticUtilities.getResourceDownloaderFactory();
ResourceDownloader rd = rdf.create(url, postData);
rd.setProperty( "URL_Connection", "Keep-Alive" );
rd = rdf.getRetryDownloader(rd, 3);
// We could report percentage to listeners, but there's no need to atm