title: Building very large spreadsheet with PHPSpreadsheet
body: <p>I'm testing out how PHPSpreadsheet works with large excel spreadsheets. Initial tests indicate that for a large spreadsheet one will quickly run out of memory.</p>
  
  <p>Is there a way to write the spreadsheet progressively?</p>
  
  <p>I have an old piece of code that I've been using for a long time to create spreadsheets from PHP. It uses a very old standard, and is due an update. But one advantage of my old code is that I could write to a file as it went rather than building the entire thing in memory, and as a result could easily cope with a very large spreadsheet without blowing the memory limit.</p>
  
  <p>Can something similar be done in PHPSpreadsheet? I've tried reading the documentation, and searched various forums, but most responses seem to be just "increase the available memory".</p>