I have started to learn Rust just recently, there's a lot I still don't understand and one of these is probably the type system... I am practicing by rewriting some of the scripts I use at work into a Rust CLI. One of the things that blocks me is the fact, that this CLI needs to send ECDSA signed payloads.

I am using k256 crate to generate a recoverable::Signature but I then want to convert it to a der signature. I noticed that there is a DerSignature trait in k256 but I have no idea how to convert one to the other.

Since k256::ecdsa::signature::Signature has a Serialize trait implemented for serde, I am converting this recoverable::Signature into a signature::Signature and then serializing it using serde. But the response I get from the server is "Signature without r or s"...

I know I'm doing something wrong, I just have no clue what. I don't know how to convert to DerSignature and I think that's the blocker for me... the backend uses elliptic.js if that helps...

This is the code I use

```
let signing_key: SigningKey = SigningKey::from(SecretKey::from_be_bytes(&raw_pk).unwrap());
let signature: recoverable::Signature = signing_key.sign_digest(hasher);
let ss: k256::ecdsa::Signature = signature.into();
let signedDto = UpdatePublicKey {
public_key: public_key.to_owned(),
algorithm: "secp256k1".to_string(),
signature: base64::encode(to_string(&ss).unwrap()),
};
println!("{}", to_string_pretty(&signedDto).unwrap());
```