code: @Override
      public byte[] sendDeliverSmResp(OutputStream os, int commandStatus, int sequenceNumber, String messageId)
              throws IOException {
          byte[] b = pduComposer.deliverSmResp(commandStatus, sequenceNumber, messageId);
          writeAndFlush(os, b);
          return b;
      }
docs: /*
  (non-Javadoc)
  
  @see org.jsmpp.PDUSender#sendDeliverSmResp(java.io.OutputStream, int, int, String)