+ /// Gets estimated satoshis of fee required per 1000 Weight-Units. This translates to:
+ /// * satoshis-per-byte * 250
+ /// * ceil(satoshis-per-kbyte / 4)
+ /// Must be no smaller than 253 (ie 1 satoshi-per-byte rounded up to ensure later round-downs
+ /// don't put us below 1 satoshi-per-byte).
+ fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u64;