I've sent a transaction with `Electrum`, but accidentally included too little fee. What can I do to speed up the transaction's confirmation or to replace it? ---- <sup>*This is a complementary question to [Why is my transaction not getting confirmed and what can I do about it?](https://bitcoin.stackexchange.com/q/9046/5406) which answers the question's broader implications and proposes mitigation mostly focused on Bitcoin Core.*</sup>