Simple implementation of Timewalk based on: https://indico.cern.ch/event/1026724/contributions/4311066/attachments/2223240/3765162/PLR_Digi_4_9_21.pdf (slide #20) if charge is < threshold+overdrive -> bunch_crossing = 1 else bunch_crossing = 0
FYI @nstyles @gmarchio @tlari @tadej @mbomben