message: D3D12: Handle MapReadAsync offset
diff: @@ -145,7 +145,7 @@ namespace d3d12 {
  ASSERT_SUCCESS(resource->Map(0, &readRange, reinterpret_cast<void**>(&data)));
  MapReadRequestTracker* tracker = ToBackend(GetDevice())->GetMapReadRequestTracker();
  - tracker->Track(this, serial, data);
  + tracker->Track(this, serial, data + start);
  }
  void Buffer::UnmapImpl() {
  