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

#### Useful skills:

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

#### Want to work on this issue?

For guidance on contributing, please read [CONTRIBUTING.md](https://github.com/bitcoin/bitcoin/blob/master/CONTRIBUTING.md) before opening your pull request.

{
    
    
    
    if (!LockDataDirectory(false)) {
        
        return false;
    }
    return true;
}
bool AppInitInterfaces(NodeContext& node)
{
    node.chain = interfaces::MakeChain(node);
    
    
    
    
    g_wallet_init_interface.Construct(node);
    return true;
}
bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)