I know people already said it, but causality, resource cleanup and error handling are all solved with Actor model in a more general, more flexible and more reli

I know people already said it, but causality, resource cleanup and error handling are all solved with Actor model in a more general, more flexible and more reliable way than nurseries. If you think reasoning about concurrency is hard, try testing and modelling it, especially for something distributed. This is where naive ideas about concurrency should start to fail and a need in solid foundation arise.