During rolling forward in `ReplayBlocks()` the UI progress starts with 0 then, once sync up again, jumps to 100%. This process can take pretty long and it would be good to show some progress steps within the RollingForwardBlock loop (`for (int nHeight = nForkHeight + 1; nHeight <= pindexNew->nHeight; ++nHeight) {`)
nBlockSequenceId = 1;
    m_failed_blocks.clear();
    setBlockIndexCandidates.clear();
}
void UnloadBlockIndex()
{
    LOCK(cs_main);
    chainActive.SetTip(nullptr);
    pindexBestInvalid = nullptr;
    pindexBestHeader = nullptr;
    mempool.clear();
    mapBlocksUnlinked.clear();
    vinfoBlockFile.clear();
    nLastBlockFile = 0;
    setDirtyBlockIndex.clear();
    setDirtyFileInfo.clear();
    versionbitscache.Clear();
    for (int b = 0; b < VERSIONBITS_NUM_BITS; b++) {
        warningcache[b].clear();
    }
    for (BlockMap::value_type& entry : mapBlockIndex) {
        delete entry.second;
    }
    mapBlockIndex.clear();
    fHavePruned = false;
    g_chainstate.UnloadBlockIndex();
}
bool LoadBlockIndex(const CChainParams& chainparams)