feat: GetAccountMode

[yash-atreya]

Motivation

Closes #9

Solution

Introduces

enum GetAccountMode {
    EthGetAccount, // If the provider supports `eth_getAccount`
    AccountCodeNonce, // If it doesn't and we have to fetch all three concurrently.
}

Above enum is cached in the BackendHandler inside a OnceLock as it only needs to set exactly once i.e on the first request when we try to determine whether the provider supports eth_getAccount or not.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[mattsse]

why does this have to be a oncelock?

[yash-atreya]

We only want to set it once on the first request, and we don't need to make get_account_req &mut self

[yash-atreya]

We're also setting the value inside Box::pin async fut

[mattsse]

I need to test this a bit because I think especially on reth this request is more expensive than doing multiple ones because of the storage root

[mattsse]

Actually we shouldn't do this because this endpoint can be significantly more expensive due to the storage root which isn't trivial to compute by certain clients