fix for: https://issues.apache.org/jira/browse/AMQNET-419

Begins to partition the DTC ugliness into a NetTXMessageConsumer so we don't have to impact performance of the non-DTC consumer in order to deal with all DTC's issues. 
diff --git a/src/main/csharp/NetTxMessageConsumer.cs b/src/main/csharp/NetTxMessageConsumer.cs
new file mode 100644
index 0000000..e93f145
--- /dev/null
+++ b/src/main/csharp/NetTxMessageConsumer.cs
@@ -0,0 +1,63 @@
+/*

+ * Licensed to the Apache Software Foundation (ASF) under one or more

+ * contributor license agreements.  See the NOTICE file distributed with

+ * this work for additional information regarding copyright ownership.

+ * The ASF licenses this file to You under the Apache License, Version 2.0

+ * (the "License"); you may not use this file except in compliance with

+ * the License.  You may obtain a copy of the License at

+ *

+ *     http://www.apache.org/licenses/LICENSE-2.0

+ *

+ * Unless required by applicable law or agreed to in writing, software

+ * distributed under the License is distributed on an "AS IS" BASIS,

+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

+ * See the License for the specific language governing permissions and

+ * limitations under the License.

+ */

+

+using System;

+using System.Collections.Generic;

+using System.Text;

+using Apache.NMS.ActiveMQ.Commands;

+

+namespace Apache.NMS.ActiveMQ

+{

+    class NetTxMessageConsumer : MessageConsumer

+    {

+        private readonly NetTxSession session;

+

+        internal NetTxMessageConsumer(Session session, ConsumerId id, ActiveMQDestination destination, 

+                                      string name, string selector, int prefetch, int maxPendingMessageCount,

+                                      bool noLocal, bool browser, bool dispatchAsync) : 

+            base(session, id, destination, name, selector, prefetch,

+                 maxPendingMessageCount, noLocal, browser, dispatchAsync)

+        {

+            this.session = session as NetTxSession;

+        }

+

+        public override void Close()

+        {

+            if (this.Closed)

+            {

+                return;

+            }

+

+            lock (this.session.TransactionContext.SyncRoot)

+            {

+                if (this.session.IsTransacted || this.session.TransactionContext.InTransaction)

+                {

+                    Tracer.DebugFormat("Consumer {0} Registering new ConsumerCloseSynchronization",

+                                       this.ConsumerId);

+                    this.session.TransactionContext.AddSynchronization(

+                        new ConsumerCloseSynchronization(this));

+                }

+                else

+                {

+                    Tracer.DebugFormat("Consumer {0} No Active TX closing normally.",

+                                       this.ConsumerId);

+                    this.DoClose();                            

+                }

+            }

+        }

+    }

+}