Okay I see no "simple" way of doing this with the current implementation of tasks using SWHTask.

The information needed (the "instance") is computed in the constructor of the lister itself, so there is no way we can retrieve this information in SWHTask.__call__().

The only sensible place where this probe could be inserted is thus within the Lister code (constructor or probably better in the run() method).

So it cannot be the same probes as the ones in SWHTask (aka 'swh_task_start_ts' and 'swh_task_end_ts') with added tags.