detect problematic resurrections

StackExchange.Redis.Tests/TestBase.cs

@@ -261,6 +261,7 @@ protected IServer GetAnyMaster(ConnectionMultiplexer muxer)
             muxer.ConnectionFailed += OnConnectionFailed;
             muxer.MessageFaulted += (msg, ex, origin) => Writer?.WriteLine($"Faulted from '{origin}': '{msg}' - '{(ex == null ? "(null)" : ex.Message)}'");
             muxer.Connecting += (e, t) => Writer.WriteLine($"Connecting to {Format.ToString(e)} as {t}");
+            muxer.Resurrecting += (e, t) => Writer.WriteLine($"Resurrecting {Format.ToString(e)} as {t}");
             muxer.Closing += complete => Writer.WriteLine(complete ? "Closed" : "Closing...");
             return muxer;
         }

StackExchange.Redis/StackExchange/Redis/PhysicalBridge.cs

@@ -467,6 +467,7 @@ internal void OnHeartbeat(bool ifConnectedOnly)
                         if (!ifConnectedOnly)
                         {
                             Multiplexer.Trace("Resurrecting " + ToString());
+                            Multiplexer.OnResurrecting(ServerEndPoint?.EndPoint, ConnectionType);
                             GetConnection(null);
                         }
                         break;

StackExchange.Redis/StackExchange/Redis/RedisSubscriber.cs

@@ -253,6 +253,7 @@ internal bool Validate(ConnectionMultiplexer multiplexer, RedisChannel channel)
         internal event Action<string, Exception, string> MessageFaulted;
         internal event Action<bool> Closing;
         internal event Action<EndPoint, ConnectionType> Connecting;
+        internal event Action<EndPoint, ConnectionType> Resurrecting;
 #else
         internal event Action<string, Exception, string> MessageFaulted
         {   // completely empty shell event, just to keep the test suite compiling
@@ -266,6 +267,10 @@ internal bool Validate(ConnectionMultiplexer multiplexer, RedisChannel channel)
         {   // completely empty shell event, just to keep the test suite compiling
             add { } remove { }
         }
+        internal event Action<EndPoint, ConnectionType> Resurrecting
+        {   // completely empty shell event, just to keep the test suite compiling
+            add { } remove { }
+        }
 #endif
 
         [Conditional("TEST")]
@@ -289,6 +294,13 @@ internal void OnConnecting(EndPoint endpoint, ConnectionType connectionType)
         {
 #if TEST
             Connecting?.Invoke(endpoint, connectionType);
+#endif
+        }
+        [Conditional("TEST")]
+        internal void OnResurrecting(EndPoint endpoint, ConnectionType connectionType)
+        {
+#if TEST
+            Resurrecting.Invoke(endpoint, connectionType);
 #endif
         }
     }