6 files declare their use of QueueWorker in Simple XML sitemap 4.x

Generator.php in src/Manager/Generator.php

SimpleSitemapCommands.php in src/Commands/SimpleSitemapCommands.php

SimplesitemapTest.php in tests/src/Functional/SimplesitemapTest.php

simple_sitemap.drush.inc in ./simple_sitemap.drush.inc

Drush (< 9) integration.

simple_sitemap.module in ./simple_sitemap.module

Main module file containing hooks.

StatusForm.php in src/Form/StatusForm.php