Fuel/Request_Response v0.0.2: More meaningful error messages

[acerone85]

Linked Issues/PRs

Closes #1311

Description

This PR follows #2362, which introduces a new version of the protocol /fuel/req_response/0.0.2 which allows to return Errors in the response. This PR makes the following changes:

• the different errors that can be returned in a response are implemented.
• The type of ResponseSender used by a peer to propagate received responses upstream is changed to allow the rrors to be propagated
• Error Responses received by a peer following a request are displayed with as log messages with warning level.

Checklist

• Breaking changes are clearly marked as such in the PR description and changelog
• New behavior is reflected in tests
• The specification matches the implemented behavior (link update PR if changes are needed)

Before requesting review

• I have reviewed the code myself
• I have created follow-up issues caused by this PR and linked them here

After merging, notify other teams

[Add or remove entries as needed]

• Rust SDK
• Sway compiler
• Platform documentation (for out-of-organization contributors, the person merging the PR will do this)
• Someone else?

[AurelienFT]

LGTM. I think you can run a search over : "#1311" in codebase and remvoe all todo related and make sure they are all addressed

[xgreenx]

Also, maybe we need to add Unknown(u32) for backward compatibility in the case if we can't deserialize the error.

[acerone85]

Tried something in 5ea9b30. There is an unknown variant, but the error code is erased away. The reason for this is that deserializing unknown values in serde has been recently implemented via the attribute serde(untagged), but this is not supported by postcard (fails with error WontImplement). See serde-rs/serde#912 (comment) for the discussion on serde(untagged). There are other alternatives proposed, such as nested enums or custom deserialization functions for a variant, but they won't either work with postcard or are too complicated imho.

Adding an Unknown variant which abstracts away the error code does at least ensure backwards compatibility.