useScrollTop is very slow

Hi, I’m testing @next and I noticed most of the time on scroll is spent on the useScrollTop hook, it leads to very long frames.

[FezVrasta]

This is the relevant code (I use react-table):

const footer = useCallback(() => {
  if (firstRow == null) {
    return null;
  }
  prepareRow(firstRow);

  return Array.from({
    length: Math.min(10, totalCount - rows.length),
  }).map((_, i) => <PlaceholderRow row={firstRow} key={i} />);
}, [prepareRow, rows.length, firstRow, totalCount]);

const components = useMemo(
  () => ({
    EmptyPlaceholder: loading ? null : EmptyComponent,
  }),
  [loading]
);

const itemContent = useCallback(
  (index) => {
    const row = rows[index];
    prepareRow(row);
    return (
      <Row
        row={row}
        onRowClick={onRowClick}
        onAddToQueue={onAddToQueue}
        onStartRead={onStartRead}
        onView={onView}
        onRemove={onRemove}
        onCompare={onCompare}
        tab={tab}
        isScrolling={isScrolling}
      />
    );
  },
  [
    isScrolling,
    onAddToQueue,
    onCompare,
    onRemove,
    onRowClick,
    onStartRead,
    onView,
    prepareRow,
    rows,
    tab,
  ]
);

<Virtuoso
  css={`
    flex: 1;
    overflow-x: hidden;
    ${style};
  `}
  totalCount={rows.length}
  endReached={onFetchMore}
  isScrolling={setIsScrolling}
  overscan={1000}
  footer={footer}
  components={components}
  defaultItemHeight={51}
  itemContent={itemContent}
/>

[FezVrasta]

I’m quite convinced the issue resides in Virtuoso, I recently tried to swap it with react-window and the performances were way better, but of course I lost all the nice features that Virtuoso provides out of the box.