# File lib/spreadsheet/excel/writer/workbook.rb, line 479
  def write_sst workbook, writer, offset
    # Offset  Size  Contents
    #      0     4  Total number of strings in the workbook (see below)
    #      4     4  Number of following strings (nm)
    #      8  var.  List of nm Unicode strings, 16-bit string length (➜ 3.4)
    strings = worksheets(workbook).inject [] do |memo, worksheet|
      memo.concat worksheet.strings
    end
    total = strings.size
    strings.uniq!
    _write_sst workbook, writer, offset, total, strings
  end