4.19 sdds::Writer page output

• name:
  Writer::write, Writer::beginPage, field setters, Writer::commitPage
• description:
  Write a complete page in one operation or construct a page incrementally inside the writer. The rvalue write overload consumes page storage and avoids a page copy. setColumn extends internal column storage in place and may be called repeatedly with increasing row ranges.
• synopsis:
  void write(const sdds::Page &page);  
  void write(sdds::Page &&page);  
  void beginPage(std::int64_t expectedRows);  
  void setParameter(std::string_view name, sdds::Scalar value);  
  void setArray(std::string_view name, sdds::ArrayData value);  
  void setColumn(std::string_view name, sdds::Values value,  
                 std::int64_t startRow = 0);  
  void commitPage();

• arguments:
  • page — Complete page compatible with the writer layout.
  • expectedRows — Expected final row count for staged construction.
  • name — Destination field name.
  • value — Field values, moved into staged storage when possible.
  • startRow — First destination row for column values.
• return value:
  None.
• exceptions:
  sdds::StateError for an invalid call sequence or incomplete page, sdds::TypeError for incompatible values, and sdds::IoError for an output failure.
• see also:
  Sections 4.7 and 4.20.