Multiple background services on a watchface

I'm experimenting with Background Services, and I wonder if it is possible to have multiple backgrounds running? As we have to return an array in `getServiceDelegate()`, it seems to be possible.

But when I have multiple services in there and set up a TemporalEvent, they both get initialised, so that's a good thing. But neither of them enters in `onTemporalEvent()`. When I have only one Background in `getServiceDelegate()`, it does actually enter the `onTemporalEvent()`.

How can I make this work with multiple Background Services?