Unsubscribe does not work correctly

[dlkeng]

Using the "unsub all" command does not actually work!
In the file "Program.cs", it appears that line 1322 never returns to complete the unsubscribe operation.

I found the following changes allow the unsubscribe to work:
Line 1303:
was: static async void Unsubscribe(string param)
change to: static async Task Unsubscribe(string param)

Line 793:
was: if (_subscribers.Count > 0) Unsubscribe("all");
change to: if (_subscribers.Count > 0) await Unsubscribe("all");

Line 790:
was: static void CloseDevice()
change to: static async Task CloseDevice()

Line 742:
was: CloseDevice();
change to: await CloseDevice();

Line 380:
was: Unsubscribe(parameters);
change to: await Unsubscribe(parameters);

Line 334:
was: CloseDevice();
change to: await CloseDevice();

Line 286:
insert: if (_selectedDevice != null) { await CloseDevice(); }

[sensboston]

@dlkeng, please provide your changes by the usual way:

• fork a repo
• create a new branch
• implement your changes (please add comments and explanations)
• commit & issue a PR