`MIN_RELAY_FEE_SAT_PER_1000_WEIGHT` is inflated 16x

[morehouse]

MIN_RELAY_FEE_SAT_PER_1000_WEIGHT is used to enforce a minimum fee bump for transaction RBFs. Per Bitcoin Core policy, this should be 1 sat/vB. Instead, we're using 16 sat/vB:

rust-lightning/lightning/src/chain/chaininterface.rs

Lines 178 to 179 in 1386bef

	/// Minimum relay fee as required by bitcoin network mempool policy.
	pub const MIN_RELAY_FEE_SAT_PER_1000_WEIGHT: u64 = 4000;

This causes RBFs to be much larger than needed in some cases.

We should be using 250 sat/kw, or maybe 253 sat/kw if we need to worry about rounding for the incremental relay feerate.

[TheBlueMatt]

Oof good catch.

[TheBlueMatt]

If this makes 0.1, great, if it doesn't, well, its not a regression nor a new feature, it generally takes users a week or two to upgrade anyway, and we can include this in 0.1.1.

[arik-so]

#3457 is merged, so closing this.