anchor.diff:      );
       final joint = _FlipperJoint(jointDef);
       world.createJoint(joint);
  -    unawaited(mounted.whenComplete(joint.unlock));
     }
   
     List<FixtureDef> _createFixtureDefs() {
  
positive.code:   /// The joint is locked when initialized in order to force the [Flipper]
    /// at its resting position.
    void lock() {
      const angle = _halfSweepingAngle;
      setLimits(
        angle * side.direction,
        angle * side.direction,
      );
    }
  
    /// Unlocks the [Flipper] from its resting position.
  
negative.code: 
      return body;
    }
  
    @override
    void onMount() {
      super.onMount();
  
      gameRef.ready().whenComplete(
            () => body.joints.whereType<_FlipperJoint>().first.unlock(),
          );
    }
  }
  
  class _FlipperSpriteComponent extends SpriteComponent with HasGameRef {
  