// activity: runnable/voidfunc()/func() -> O
// function result will be held during measurement
static long measureTotalObjectSize(O activity, S desc) {
  long mem1 = memoryUsedAfterGC();
  O result = callF(activity);
  long mem2 = memoryUsedAfterGC();
  long diff = mem2-mem1;
  print("Memory used" + (nempty(desc) ? " for " + desc : "") + ": " + toK(diff) + " K");
  ret diff;
}

static long measureTotalObjectSize(O activity) {
  ret measureTotalObjectSize(activity, shorten(str(activity), 40));
}