void step(double dt)

Steps the action forward by the specified time, typically there is no need to directly call this method.

Source

void step(double dt) {
  for (int i = _actions.length - 1; i >= 0; i--) {
    Action action = _actions[i];
    action.step(dt);

    if (action._finished) {
      action._added = false;
      _actions.removeAt(i);
    }
  }
}