Minimal repro steps
1. Start Microsoft.AspNet.SignalR.Client.JS.Tests project
2. Click Rerun "Hub Group Facts: longPolling: Hub can send and receive messages from groups. (Functional)" multiple times until you get
NOTE: it may take several times to reproduce the issue, I ran it 1000 times and got 3 repros.
Order Topics with no subscriptions correctly by LastUsed DateTime
- Only Kill topics if we are absolutely sure they have no subscriptions