configuration property Null safety
The settings to pass to the rowDecorations when painting, so that they can resolve images appropriately. See ImageProvider.resolve and BoxPainter.paint.
Implementation
ImageConfiguration get configuration => _configuration;Implementation
set configuration(ImageConfiguration value) {
  assert(value != null);
  if (value == _configuration) {
    return;
  }
  _configuration = value;
  markNeedsPaint();
}