code: public void toPdf(OutputStream os) throws IOException {
                  StringBuffer off = new StringBuffer("0000000000").append(offset);
                  off.delete(0, off.length() - 10);
                  StringBuffer gen = new StringBuffer("00000").append(generation);
                  gen.delete(0, gen.length() - 5);
  
                  off.append(' ').append(gen).append(generation == GENERATION_MAX ? " f \n" : " n \n");
                  os.write(getISOBytes(off.toString()));
              }
docs: Returns the PDF representation of this <CODE>PdfObject</CODE>.
  @param os
  @throws IOException