There are some potential feefilter cleanups mentioned and motivated in comment https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-805808485 . If you address the locking one, please be careful and make sure that `round()` is only called under a lock. See https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-807992199

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{
    CNodeState *state = State(nodeid);
    assert(state != nullptr);
    
    std::map<uint256, std::pair<NodeId, std::list<QueuedBlock>::iterator> >::iterator itInFlight = mapBlocksInFlight.find(hash);
    if (itInFlight != mapBlocksInFlight.end() && itInFlight->second.first == nodeid) {
        if (pit) {
            *pit = &itInFlight->second.second;
        }
        return false;
    }
    
    MarkBlockAsReceived(hash);
    std::list<QueuedBlock>::iterator it = state->vBlocksInFlight.insert(state->vBlocksInFlight.end(),
            {hash, pindex, pindex != nullptr, std::unique_ptr<PartiallyDownloadedBlock>(pit ? new PartiallyDownloadedBlock(&m_mempool) : nullptr)});
    state->nBlocksInFlight++;
    state->nBlocksInFlightValidHeaders += it->fValidatedHeaders;
    if (state->nBlocksInFlight == 1) {
        
        state->m_downloading_since = GetTime<std::chrono::microseconds>();
    }
    if (state->nBlocksInFlightValidHeaders == 1 && pindex != nullptr) {
        nPeersWithValidatedDownloads++;
    }
    itInFlight = mapBlocksInFlight.insert(std::make_pair(hash, std::make_pair(nodeid, it))).first;
    if (pit)
        *pit = &itInFlight->second.second;
    return true;
}
void PeerManagerImpl::MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid)