+
+ /// Sign an invoice's preimage (note that this is the preimage of the invoice, not the HTLC's
+ /// preimage). By parameterizing by the preimage instead of the hash, we allow implementors of
+ /// this trait to parse the invoice and make sure they're signing what they expect, rather than
+ /// blindly signing the hash.
+ fn sign_invoice(&self, invoice_preimage: Vec<u8>) -> Result<RecoverableSignature, ()>;