Hey Alexandre Pauwels.
Not sure that you still interesting timestamps-case in HLF (but may be should be helpful for someone else)
Found some interesting fork of HLF that focused on timestamps here:

https://github.com/aritramitra14/fabric/tree/timefabric

https://uwspace.uwaterloo.ca/bitstream/handle/10012/16784/Mitra_Aritra.pdf

https://svr-sk818-web.cl.cam.ac.uk/keshav/wiki/images/1/1a/Time_Fabric_FAB_21.pdf