if ( myUdhElements == null) { return null; }
    public byte[] getUserDataHeaders()    {        ByteArrayOutputStream baos = new ByteArrayOutputStream(100);        try        {            for(int i=0; i < myUdhElements.length; i++)            {                myUdhElements[i].writeTo(baos);            }        }        catch (IOException ioe)        {            // Shouldn't happen.            throw new RuntimeException("Failed to write to ByteArrayOutputStream");        }        return baos.toByteArray();    }