LBM will call this method to attempt to retrieve a LBMMessage object instance that it can use
instead of creating a new instance to reduce garbage collection. It will reset the state of
the LBMMessage once it is retrieved and then use it as if it were a new instance. Returning null
causes LBM to create a new instance as if there were no recycler.

C# |
public virtual LBMMessage retrieveMessage( Object cbObj )

- cbObj (Object)
- The callback object token that was stored when setting LBMObjectRecycler in the attributes

Either null or a valid LBMMessage object will be returned