function getUnboundedScrollPosition(scrollable) {
  if (scrollable.Window && scrollable instanceof scrollable.Window) {
    return {
      x: scrollable.pageXOffset || scrollable.document.documentElement.scrollLeft,
      y: scrollable.pageYOffset || scrollable.document.documentElement.scrollTop
    };
  }
  return {
    x: scrollable.scrollLeft,
    y: scrollable.scrollTop
  };
}
Executed within the scope of the `Transaction` instance. Consider these as
being member methods, but with an implied ordering while being isolated from
each other.