[Click] Change data rate during execution

[Panos Μatzakos]

Hello, i would like to use an element packet source (like RatedSource) in which the rate would not be stable but it could change during the execution. For example, send the first 100 packets with  20 packs/sec rate, the next 100 with 40 packs/sec rate etc... I think there is no standard Click element which does sth like that. So do you think it would be easy to modify RatedSource  and if so which changes should be done in general?                                                                                               Thanks