Feature request: non nullable Stream, connected device, expose VID & PID

[DennisSchm]

Hello! First things first: Thank you for this great plugin, which really fills a niche.

I had great success so far with it but found a few things I wish this plugin supports.

Non nullable MidiDevice Stream: I get that the Stream for MidiPackages has to be nullable since it may be that you are not connected to a MidiDevice but does the onMidiSetupChanged method must yield one as well? If yes, why is that?

Streamable connection state: It would be nice to have a stream of all connected/active devices. That way you could subscribe to their midi packages in an async way. It would also be a great benefit if you could watch the individual connection state of a device.

Vendor-ID and Product-ID of devices: it would be nice if both would be exposed.

simpler midi packets: It would be fantastic if the midi packets would include some getters that does the splitting of the raw data.

Thank you again for all the good work so far!