code: void advanceContextToNextPortableToken(int factoryId, int classId, int version) throws IOException {
          cd = serializer.setupPositionAndDefinition(in, factoryId, classId, version);
          initFinalPositionAndOffset(in, cd);
      }
docs: When we advance in the token navigation we need to re-initialise the class definition with the coordinates
  of the new portable object in the context of which we will be navigating further.