Thanks for your help and assessment of the problem. It already filed a bug report: FB9919924 Unfortunately all my bug reports of the last year never got any attention.

Thank you for your answer. Unfortunately in this case this would not work, because Objective-C must be able to call these methods exactly with the specified names otherwise my app would not konform to the CBPeripheralDelegate protocol.

Sorry, my error. I assumed this would be the case. Unfortunately top level code and swift concurrency does not yet work the way you expected. And I misremembered how @main works.

Thank you very much. That was exactly the solution I was looking for!