scrollOffsetX property
      
      ViewportOffset?
      get
      scrollOffsetX
      
    
    
    
Implementation
ViewportOffset? get scrollOffsetX => _scrollOffsetX;
      
      set
      scrollOffsetX
      (ViewportOffset? value) 
      
    
    
    
Implementation
set scrollOffsetX(ViewportOffset? value) {
  if (value == _scrollOffsetX) return;
  _scrollOffsetX?.removeListener(scrollXListener);
  _scrollOffsetX = value;
  _scrollOffsetX?.addListener(scrollXListener);
  markNeedsLayout();
}