Some async init_device confusion

This is more of a question than an issue perhaps, but it is confusing behavior. I have discussed it with Anton and we agreed to put it here.

In an asyncio green-mode device with a non-async init_device method, it does not work to call super().init_device() to e.g. get device properties. The call seems to do nothing, I suppose because it is a coroutine and needs to be awaited. Instead I have to use super().get_device_properties(). The other solution is to make the method async, and use await super().init_device(). But it is not obvious that init_device should be async, as it works anyway (though the asyncio example in the docs do use async).

This may be a bit obscure, but it is kind of confusing, it took me a while to figure out why my properties were not read. It would be nice if it could be fixed to "just work", else it should perhaps be more clearly documented.