title: WCF Cast error "Unable to cast object of type 'X' to type 'X'
body: <p>I develop WCF Publisher/Subscriber model, Publisher to develop in WCF service library and to host in windows service, its running fine. After to create a Proxy for that endpoints using 'SvcUtil'. and to merge to subscriber to develop in windows application. when i connect to publisher, </p>
  
  <p>I get error "WCF Cast error "Unable to cast object of type 'X' to type 'X'"</p>
  
  <p>i debug the code this line to rise the error
  IEvent Subscriber = OperationContext.Current.GetCallbackChannel();</p>