/** Creates an XMLRPC call from the given method name and parameters and sends it */
protected void writeCall(String methodName, Object[] args) throws Exception {
huc = u.openConnection();
huc.setDoOutput(true);
huc.setDoInput(true);
huc.setUseCaches(false);
huc.setRequestProperty("Content-Type", "binary/message-pack");
huc.setReadTimeout(0);
OutputStream os = huc.getOutputStream();
Packer pk = new Packer(os);
pk.packArray(args.length + 1);
pk.pack(methodName);
for (Object o : args) pk.pack(o);
os.close();
}