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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* Bitcoin protocol messages
* Bitcoin Core P2P design
* Running our unit and functional tests

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{
    const ArgsManager& args = *Assert(node.args);
    const CChainParams& chainparams = Params();
    
    if (!CreatePidFile(args)) {
        
        return false;
    }
    if (!init::StartLogging(args)) {
        
        return false;
    }
    LogPrintf("Using at most %i automatic connections (%i file descriptors available)\n", nMaxConnections, nFD);
    
    if (args.IsArgSet("-datadir") && !fs::path(args.GetArg("-datadir", "")).is_absolute()) {
        LogPrintf("Warning: relative datadir option '%s' specified, which will be interpreted relative to the " 
                  "current working directory '%s'. This is fragile, because if bitcoin is started in the future "
                  "from a different location, it will be unable to locate the current data files. There could "
                  "also be data loss if bitcoin is started while in a temporary directory.\n",
                  args.GetArg("-datadir", ""), fs::current_path().string());
    }
    InitSignatureCache();
    InitScriptExecutionCache();
    int script_threads = args.GetArg("-par", DEFAULT_SCRIPTCHECK_THREADS);
    if (script_threads <= 0) {