message: Workaround for screenshot in save_screenshot being empty
diff: @@ -30,6 +30,12 @@ fn save_screenshot() {
  .unwrap();
  graphics::draw(c, &tri_mesh, graphics::DrawParam::default()).unwrap();
  graphics::present(c).unwrap();
  +
  + // Right now what we're screenshoting is not the front buffer, but the backbuffer.
  + // I.e. since we're double buffering we're always one picture in the past.
  + // Querying the front buffer can be much slower, so probably we should keep it as is.
  + graphics::present(c).unwrap();
  +
  let screenshot = graphics::screenshot(c).unwrap();
  screenshot
  .encode(c, graphics::ImageFormat::Png, "/screenshot_test.png")
  