Create MessageProducer with a sync call in order to catch creation errors.
Fixes [AMQNET-AMQNET-523]. (See https://issues.apache.org/jira/browse/AMQNET-AMQNET-523)

diff --git a/src/main/csharp/Session.cs b/src/main/csharp/Session.cs
index ef91700..e09f6b1 100755
--- a/src/main/csharp/Session.cs
+++ b/src/main/csharp/Session.cs
@@ -460,7 +460,7 @@
                 producer.ProducerTransformer = this.ProducerTransformer;
 
                 this.AddProducer(producer);
-                this.Connection.Oneway(producer.ProducerInfo);
+                this.Connection.SyncRequest(producer.ProducerInfo);
             }
             catch(Exception)
             {