Uapmd Undo State
@Structure.FieldOrder(value = ["busy", "compound_open", "gesture_open", "can_undo", "can_redo", "dirty", "compound_description", "undo_description", "redo_description", "history_size_in_bytes", "maximum_history_size_in_bytes", "current_state_id", "saved_state_id" ] )