Similar to the behaviour of MassMessage
The hook used in MassMessage can be seen at https://github.com/wikimedia/mediawiki-extensions-MassMessage/blob/master/MassMessage.hooks.php#L103
The method counting the jobs can be seen at https://github.com/wikimedia/mediawiki-extensions-MassMessage/blob/master/includes/MassMessage.php#L207
Job names:
- massActionChangeSaverJob
- massActionChangeSaverSpawnerJob
- massActionTargetListJob