Signer API discussion

[frol]

I moved this discussion from our Telegram group

Original feedback (from me):

Signer::new(Signer::from_seed_phrase()) looks really odd to me. T::from_* should return T, but it is not the case somehow

@akorchyn responded:

Yeah, agree. I want to have it simple. And to have ability to get any implementation at one place. Thast's why I put in the wrapper these constructors of other types. But it's confusing.
Maybe, enum. Signer::new(SignerType::Seed), SignerType::SeedWithHdPhrase, etc

[frol]

@akorchyn Do you really need Signer struct at all? I would expect that the method where you pass (with_signer()), you'd just expect anything that implements Signer trait (and KeystoreSigner, LedgerSigner, and SignersPool to implement Signer trait)

[akorchyn]

Well, we also need to cache nonce for consecutive calls. I think it's easier to maintain by having simple wrapper than implement it for every signer

[frol]

I see... Let me think about this challenge for a bit.