https://travis-ci.org/github/bitcoin/bitcoin/jobs/679885530#L8791
{
        gArgs.LockSettings([&](util::Settings& settings) {
            if (value.isNull()) {
                settings.rw_settings.erase(name);
            } else {
                settings.rw_settings[name] = value;
            }
        });
        return gArgs.WriteSettingsFile();
    }
    void requestMempoolTransactions(Notifications& notifications) override
    {
        if (!m_node.mempool) return;
        LOCK2(::cs_main, m_node.mempool->cs);
        for (const CTxMemPoolEntry& entry : m_node.mempool->mapTx) {
            notifications.transactionAddedToMempool(entry.GetSharedTx(), 0 );
        }
    }
    NodeContext& m_node;
};
} 
} 
namespace interfaces {
std::unique_ptr<Node> MakeNode(NodeContext* context) { return MakeUnique<node::NodeImpl>(context); }
std::unique_ptr<Chain> MakeChain(NodeContext& context) { return MakeUnique<node::ChainImpl>(context); }
}