Tests: better logging on Cluster.ConnectUsesSingleSocket

Not sure why this is failing...we need more info. It could be socke exhaustion on the box.

StackExchange.Redis.Tests/Cluster.cs

@@ -38,22 +38,38 @@ public void ExportConfiguration()
         [Fact]
         public void ConnectUsesSingleSocket()
         {
-            for (int i = 0; i < 10; i++)
+            using (var sw = new StringWriter())
+            {
+                try
+                {
+                    for (int i = 0; i < 5; i++)
                     {
-                using (var muxer = Create(failMessage: i + ": "))
+                        using (var muxer = Create(failMessage: i + ": ", log: sw))
                         {
                             foreach (var ep in muxer.GetEndPoints())
                             {
                                 var srv = muxer.GetServer(ep);
                                 var counters = srv.GetCounters();
-                        Output.WriteLine(i + "; interactive, " + ep);
+                                Output.WriteLine($"{i}; interactive, {ep}, count: {counters.Interactive.SocketCount}");
+                                Output.WriteLine($"{i}; subscription, {ep}, count: {counters.Subscription.SocketCount}");
+                            }
+                            foreach (var ep in muxer.GetEndPoints())
+                            {
+                                var srv = muxer.GetServer(ep);
+                                var counters = srv.GetCounters();
                                 Assert.Equal(1, counters.Interactive.SocketCount);
-                        Output.WriteLine(i + "; subscription, " + ep);
                                 Assert.Equal(1, counters.Subscription.SocketCount);
                             }
                         }
                     }
                 }
+                finally
+                {
+                    // Connection info goes at the end...
+                    Output.WriteLine(sw.ToString());
+                }
+            }
+        }
 
         [Fact]
         public void CanGetTotalStats()