code: public byte[] serializeDoc() throws IOException {
  		XmlDomWriter xw = new XmlDomWriter();
          ByteArrayOutputStream fout = new ByteArrayOutputStream();
          xw.setOutput(fout, null);
          fout.write(XmpWriter.XPACKET_PI_BEGIN.getBytes("UTF-8"));
          fout.flush();
          NodeList xmpmeta = domDocument.getElementsByTagName("x:xmpmeta");
          xw.write(xmpmeta.item(0));
          fout.flush();
  		for (int i = 0; i < 20; i++) {
  			fout.write(XmpWriter.EXTRASPACE.getBytes());
  		}
          fout.write(XmpWriter.XPACKET_PI_END_W.getBytes());
          fout.close();
          return fout.toByteArray();
  	}
docs: Writes the document to a byte array.