sclass ScreenShooter implements AutoCloseable {
  transient L onNewImage; // L<Runnable|voidfunc(BufferedImage)>
  
  transient BufferedImage latestImage;
  double interval = 1.0;
  transient java.util.Timer timer;
  
  ScreenShooter start() {
    timer = doEvery(interval, r {
      latestImage = shootScreen2();
      pcallFAll(onNewImage, latestImage);
      vmBus_send newScreenShot(latestImage);
    });
    this;
  }
  
  public void close() {
    dispose timer;
  }
}