buildHeader method
Header item builder Receives BuildContext and StickyState
If headerBuilder and headerStateBuilder not specified, this method won't be called
Second param StickyState will be passed if watchStickyState is TRUE
Implementation
Widget buildHeader(BuildContext context, [StickyState<I>? state]) {
if (state == null) {
return headerBuilder!(context);
}
return headerStateBuilder!(context, state);
}