message: added parameter in dataman doc
diff: @@ -36,6 +36,11 @@ The DataMan engine takes the following parameters:
  Enabling double buffer will cause extra overhead for managing threads and buffer queues, but will improve the continuity of data steps for the reader, for the pub/sub mode.
  Advice for generic uses cases is to keep the default values, true for reader and false for writer.
  +6. ``TransportMode``: Default **fast**. The fast mode is optimized for latency-critical applications.
  + It enforces readers to only receive the latest step.
  + Therefore, in cases where writers are faster than readers, readers will skip some data steps.
  + The secure mode ensures that all steps are received by readers, by sacrificing performance compared to the fast mode.
  +
  =============================== ================== ================================================
  **Key** **Value Format** **Default** and Examples
  =============================== ================== ================================================
  @@ -44,6 +49,7 @@ The DataMan engine takes the following parameters:
  Timeout integer **5**, 10, 30
  RendezvousReaderCount integer **1**, 0, 3
  DoubleBuffer bool **true** for reader, **false** for writer
  + TransportMode string **fast**, secure
  =============================== ================== ================================================
  