new SideHeaderListView(
    // Set how many items the list has
    itemCount: items.length,
    
    // Set the height of the item widgets. For now this has to be a fixed height
    itemExtend: 150.0,
    
    // Set the header builder, this needs to return the widget for the side header
    headerBuilder: (BuildContext context, int index){
      return new HeaderWidget(items[index].startDate);
    },
    
    // Set the item builder, this is everything in the row without the header
    itemBuilder: (BuildContext context, int index){
      return new ListItem(items[index]);
    },
    
    // HasSameHeader will be used to know whether the header has to be shown for a position 
    hasSameHeader: (int a, int b){
      return items[a].day == items[b].day;
    },
  );