code: public static void apply(Widget widget, Double top, Double bottom, Double offset) {
          MaterialPushpin pushpin = new MaterialPushpin();
          pushpin.setWidget(widget);
          pushpin.setTop(top);
          pushpin.setBottom(bottom);
          pushpin.setOffset(offset);
          pushpin.apply();
      }
docs: A pushpinned element has 3 states. One above and below the scrolling threshold,
  and the pinned state where the element becomes fixed.
  
  @param widget - Target widget to apply the pushpin feature
  @param top    - The distance in pixels from the top of the page where the element becomes fixed. (Default: 0)
  @param bottom - The distance in pixels from the top of the page where the elements stops being fixed. (Default: Infinity)
  @param offset - The offset from the top the element will be fixed at. (Default: 0)