Just giving it a go

I think there's a race in ReconfigureAsync with clusters here where the last subscription to finish is left out...but not seeing it yet. Tests show it over and over, though.

StackExchange.Redis.Tests/Cluster.cs

@@ -46,7 +46,7 @@ public async Task ConnectUsesSingleSocket()
                     {
                         using (var muxer = Create(failMessage: i + ": ", log: sw))
                         {
-                            await Task.Delay(100);
+                            await Task.Delay(500);
                             foreach (var ep in muxer.GetEndPoints())
                             {
                                 var srv = muxer.GetServer(ep);