Preloader background in OpenFL-bitfive

package ;
import flash.display.Bitmap;
import flash.display.BitmapData;

/**
 * Working preloader background example for openfl-bitfive
 * Resource "etc/preloader.png" should be defined before all other assets in application.xml:
 * <assets path="assets/etc" rename="etc" include="preloader.png" />
 *
 * @author YellowAfterlife
 */
class Preloader extends NMEPreloader {
    /// Background image element
    var _background:Bitmap;
    /// Whether background was successfully painted.
    var _painted:Bool = false;

    public function new() {
        super();
        _background = new Bitmap(new BitmapData(Std.int(getWidth()), Std.int(getHeight()), true, 0));
        addChildAt(_background, 0);
    }

    override public function onUpdate(filesLoaded:Int, filesTotal:Int):Void {
        super.onUpdate(filesLoaded, filesTotal);
        if (!_painted) {
            try { // attempt to draw the preloader background:
                _background.bitmapData.draw(openfl.Assets.getBitmapData("etc/preloader.png"));
                _painted = true;
            } catch (z:Dynamic) {
                // likely not loaded yet
            }
        }
    }
}