function useBlockCountsImpl (accountId: string, sessionRewards: SessionRewards[]): u32[] {
  const { api } = useApi();
  const mountedRef = useIsMountedRef();
  const indexes = useCall<DeriveSessionIndexes>(api.derive.session?.indexes);
  const current = useCall<u32>(api.query.imOnline?.authoredBlocks, [indexes?.currentIndex, accountId]);