Clarify what Disconnected status of null means on different platforms

[eddieSullivan]

Looking at the documentation for State.Disconnected, it briefly describes the status field and says "Always null for Javascript target." However I see it as null sometimes on Android as well, and it's not clear what that means.

I do see one place in the code where it goes to null. I would argue that Unknown would be a better option here, since it indicates we don't know why it disconnected. I can reproduce that consistently by just unplugging the device the phone is connected to.

[twyatt]

Ya, Unknown is more explicit than null for representing that we don't have a connection state yet.
Will try to find some time soon to drop null as a potential state (and update the documentation accordingly).