A client session 'move' event. This event is processed on the client session's old node to mark the session as relocating. Once the session is marked for relocation, the associated session's event processing is suspended until the session is relocated to the new node.
When this event commits, a task is scheduled to commence preparation for the client session to relocate. The first action is to obtain a relocation key from the new node and notify interested parties to prepare for relocation. See {@link ClientSessionHandler#MoveAction}for details.