message: Reapplied index after updating titles
diff: - (void)setTitles:(NSArray<NSString *> *)titles
  {
  + NSInteger _selectedIndex = self.selectedSegmentIndex;
  [self removeAllSegments];
  for (NSString *title in titles) {
  [self insertSegmentWithTitle:title atIndex:self.numberOfSegments animated:NO];
  }
  + self.selectedSegmentIndex = _selectedIndex;
  }
  - (void)setBackgroundColor:(UIColor *)backgroundColor
  