I would really like to understand how you can create an extension that allows interacting with a running kernel.
It seems like a very basic functionality to be able to interact with a running kernel in order to create either basic live monitors or widgets like iPywidgets for the classic notebook interface.
I’ve asked a question about it before How to create a jupyter-lab extension that interacts with a running kernel but either I am missing something obvious or it is not really clear where this is documented.