message: Always do the error threshold check, we may even reach it for 0.0
diff: @@ -341,7 +341,6 @@ namespace ospray {
  auto end = std::unique(tilesForFrame.begin(), tilesForFrame.end());
  tilesForFrame.erase(end, tilesForFrame.end());
  - if (errorThreshold > 0.0) {
  // Filter any tiles which are finished due to reaching the
  // error threshold. This should let TBB better allocate threads only
  // to tiles that actually need work.
  @@ -355,7 +354,6 @@ namespace ospray {
  });
  tilesForFrame.erase(end, tilesForFrame.end());
  }
  - }
  tasking::parallel_for(tilesForFrame.size(), [&](size_t taskIndex) {
  const int tileIndex = tilesForFrame[taskIndex];
  