code: public byte[] getMessage() {
          byte request[] = new byte[1 + 7 * records.length];
  
          int offset = 0;
          request[offset++] = (byte)(request.length - 1);
  
          for (RecordRequest record : records) {
              record.getRequest(request, offset);
              offset += 7;
          }
          return request;
      }
docs: getMessage
  @return the PDU message