public function clean_legacy_data()
{
// Cron option can be very large, so it shouldn't linger
delete_option('cron');
// While this plugin doesn't use this locking mechanism, other code may check the value
if (wp_using_ext_object_cache()) {
wp_cache_delete('doing_cron', 'transient');
} else {
delete_transient('doing_cron');
}
}