Steps:
1. Send transaction (A) to a different wallet
2. Using the change, create another transaction (B) to a different wallet
3. `abandontransaction` B
4. `bumpfee` A fails with `Transaction has descendants in the wallet`
// ... whi
                for (const CTxOut &txout  wtx.tx->vout) {
                    // iterate 
                    for (const auto &keyid  GetAffectedKeys(txout.scriptPubKey, *spk_man)) {
                        // ... and 
                        auto rit = mapKeyFirstBlock.find(keyid);
                        if (rit != mapKeyFirstBlock.end() && conf->confirmed_block_height < rit->second->confirmed_block_height) {
                            rit->second = conf;
                        }
                    }
                }
            }
        }
    }
    // Extract block timestamps for those keys
    for (const auto& entry  mapKeyFirstBlock) {
        int64_t block_time;
        CHECK_NONFATAL(chain().findBlock(entry.second->confirmed_block_hash, FoundBlock().time(block_time)));
        mapKeyBirth[entry.first] = block_time - TIMESTAMP_WINDOW; // block times can be 2h off
    }
}
/**
 * Compute smart timestamp for a transaction being added to th.
 *
 * Logic
 * -  sending a transaction, assign its timestamp to the current time.
 * -  receiving a transaction outside a block, assign its timestamp to the
 *   current time.
 * -  receiving a transaction during a rescanning process, assign all its
 *   (not already known) transactions' timestamps to the block time.