message: comment for PAGE_SIZE
diff: @@ -29,7 +29,10 @@ const UNPAGINATION_PADDING = 6000;
  // The number of milliseconds to debounce calls to onUnfillRequest, to prevent
  // many scroll events causing many unfilling requests.
  const UNFILL_REQUEST_DEBOUNCE_MS = 200;
  -
  +// _updateHeight makes the height a ceiled multiple of this so we
  +// don't have to update the height too often. It also allows the user
  +// to scroll past the pagination spinner a bit so they don't feel blocked so
  +// much while the content loads.
  const PAGE_SIZE = 400;
  let debuglog;
  