message: Handle error somewhat better
diff: @@ -39,11 +39,11 @@ public:
  {
  assert(file_);
  - int err = fclose(file_);
  + int res = fclose(file_);
  - assert(err == 0);
  + assert(res != EOF);
  - VSNRAY_UNUSED(err);
  + VSNRAY_UNUSED(res);
  }
  private:
  