* in a trace set. It must be called each time a trace is added/removed from
* the traceset. It could be more efficient to call it only once a bunch
* of traces are loaded, but the calculation is not long, so it's not
* in a trace set. It must be called each time a trace is added/removed from
* the traceset. It could be more efficient to call it only once a bunch
* of traces are loaded, but the calculation is not long, so it's not