fix thread-race on _parent

StackExchange.Redis.Tests/Booksleeve/PubSub.cs

@@ -95,7 +95,7 @@ public async Task PubSubGetAllAnyOrder()
                     {
                         data.Add(int.Parse(Encoding.UTF8.GetString(val)));
                         pulse = data.Count == count;
-                        if ((data.Count % 10) == 99) Output.WriteLine(data.Count.ToString());
+                        if ((data.Count % 100) == 99) Output.WriteLine(data.Count.ToString());
                     }
                     if (pulse)
                     {
@@ -151,7 +151,7 @@ async Task RunLoop()
                         {
                             data.Add(i);
                             if (data.Count == count) break;
-                            if ((data.Count % 10) == 99) Output.WriteLine(data.Count.ToString());
+                            if ((data.Count % 100) == 99) Output.WriteLine(data.Count.ToString());
                         }
                     }
                     lock (syncLock)
@@ -210,7 +210,7 @@ public async Task PubSubGetAllCorrectOrder_OnMessage_Sync()
                     {
                         data.Add(i);
                         if (data.Count == count) pulse = true;
-                        if ((data.Count % 10) == 99) Output.WriteLine(data.Count.ToString());
+                        if ((data.Count % 100) == 99) Output.WriteLine(data.Count.ToString());
                     }
                     if (pulse)
                     {
@@ -271,7 +271,7 @@ public async Task PubSubGetAllCorrectOrder_OnMessage_Async()
                     {
                         data.Add(i);
                         if (data.Count == count) pulse = true;
-                        if ((data.Count % 10) == 99) Output.WriteLine(data.Count.ToString());
+                        if ((data.Count % 100) == 99) Output.WriteLine(data.Count.ToString());
                     }
                     if (pulse)
                     {

StackExchange.Redis/StackExchange/Redis/ChannelMessageQueue.cs

@@ -157,7 +157,7 @@ internal void UnsubscribeImpl(Exception error = null, CommandFlags flags = Comma
             var parent = _parent;
             if (parent != null)
             {
-                _parent.UnsubscribeAsync(_redisChannel, HandleMessage, flags);
+                parent.UnsubscribeAsync(_redisChannel, HandleMessage, flags);
                 _parent = null;
                 _channel.Writer.TryComplete(error);
             }
@@ -167,7 +167,7 @@ internal async Task UnsubscribeAsyncImpl(Exception error = null, CommandFlags fl
             var parent = _parent;
             if (parent != null)
             {
-                await _parent.UnsubscribeAsync(_redisChannel, HandleMessage, flags);
+                await parent.UnsubscribeAsync(_redisChannel, HandleMessage, flags);
                 _parent = null;
                 _channel.Writer.TryComplete(error);
             }