Thank you for sharing your code, what saved us a lot of time! For the sake of completeness, you need to mention, that the subscriber needs to be added in an extended services.xml ([yourPlugin]/src/Resources/config/services.xml) like:
Thank you for sharing your code, what saved us a lot of time! For the sake of completeness, you need to mention, that the subscriber needs to be added in an extended services.xml ([yourPlugin]/src/Resources/config/services.xml) like: