4.20 sdds::Writer update and lifecycle operations

• name:
  Writer::updatePage, Writer::sync, Writer::disconnect, Writer::reconnect, Writer::close
• description:
  Publish rows appended to an updateable final page, synchronize output, temporarily release a path handle, reopen it after file-identity checks, or finalize a writer. Compatible uncompressed row-major files can be updated in place. Automatic uses an adjacent-file atomic rewrite for compressed or column-major files; InPlaceOnly rejects them.
• synopsis:
  void updatePage(bool flushRows = false);  
  void sync();  
  void disconnect();  
  void reconnect();  
  void close();

• arguments:
  • flushRows — Flush newly written row data while publishing the updated row count.
• return value:
  None.
• exceptions:
  sdds::StateError for an unsupported strategy or call sequence and sdds::IoError for flush, synchronization, reconnect, replacement, or atomic-rewrite failures.
• see also:
  Sections 4.17 and 4.15.