feat(primitives): add Signature::as_rsy method

[mablr]

Motivation

Close #1040

Solution

add Signature::as_rsy method to obtain raw signature bytes, with y_parity as it is

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[mablr]

I’m not sure if this is the most appropriate name for this Signature helper.

[onbjerg]

this is eip-2098, so let's find an appropriate name for this and link to the eip?

ref https://eips.ethereum.org/EIPS/eip-2098

[mablr]

There is as_erc2098():

core/crates/primitives/src/signature/sig.rs

Line 194 in 52a263d

pub fn as_erc2098(&self) -> [u8; 64] {

Here as far as I understand we do uncompacted, so the following may be suitable:

• as_erc2098_uncompacted()
• as_eip2098_uncompacted()

[mattsse]

hmm, actually, this isn't eip-2098, becasue we have that already and that is different

[mablr]

hmm, actually, this isn't eip-2098, becasue we have that already and that is different

I agree

(I edited my previous comment just before yours, sorry for the possible confusion)

[onbjerg]

erhhh, unsure then. maybe as_rsy? to highlight what it does. we already have a as_bytes and honestly I think maybe that's a mistake too because it doesn't really tell you the format (but we can't change that right now)

[mattsse]

lgtm, pending @onbjerg