Set (and enable) the context callback for topic-less immediate mode messages.

C# |
public void setImmediateMessageCallback( LBMImmediateMessageCallback cb, Object cbArg, LBMEventQueue evq )

- cb (LBMImmediateMessageCallback)
- LBMImmediateMessageCallback callback delegate.
- cbArg (Object)
- Callback object.
- evq (LBMEventQueue)
- LBMEventQueue on which to place received topic-less immediate-mode messages (can be null).