title: Spreadsheet_Excel_Writer get file content
body: <p>I need to attach an XLS-file to e-mail via PHP.
  The Problem is - <code>Spreadsheet_Excel_Writer</code> send a HTTP Header to a browser an then the content. <code>Spreadsheet_Excel_Writer</code> API has no any functions like <code>get_content</code> to become the file content directly. I don't want to save the file first, I just want to jump this step over, saving the content directly as attachment.
  Any ideas?</p>
  
  <p>Thx a lot.</p>