Introduce a standalone gas estimate type

[mattsse]

Describe the feature

with

reth/crates/rpc/rpc-eth-api/src/node.rs

Line 12 in bd8c4ec

pub trait RpcNodeCore: Clone + Send + Sync {

we now have a way to plugin additional logic into the rpc stack:

for example:

reth/crates/rpc/rpc-eth-api/src/helpers/spec.rs

Lines 17 to 18 in bd8c4ec

	pub trait EthApiSpec:
	RpcNodeCore<

we can use this as the entrypoint to abstract away more evm specific logic, for example gas estimation:

reth/crates/rpc/rpc-eth-api/src/helpers/call.rs

Lines 51 to 59 in bd8c4ec

	/// Estimate gas needed for execution of the `request` at the [`BlockId`].
	fn estimate_gas_at(
	&self,
	request: TransactionRequest,
	at: BlockId,
	state_override: Option<StateOverride>,
	) -> impl Future<Output = Result<U256, Self::Error>> + Send {
	Call::estimate_gas_at(self, request, at, state_override)
	}

which has a very simple interface

but perhaps it would be simpler if we introduce a new trait and type like EthApiCore {type Estimator;} so that it can plugged into the rpc stack by implementing

so we can do trait Call: EthApiCore< Estimator: impl trait GasEstimator> or similar.

this can then be plugged into the rpc type like

reth/crates/optimism/rpc/src/eth/mod.rs

Line 116 in bd8c4ec

impl<N> RpcNodeCore for OpEthApi<N>

this means we need to convert this into a standalone type first:

reth/crates/rpc/rpc-eth-api/src/helpers/call.rs

Lines 684 to 703 in bd8c4ec

	/// Estimate gas needed for execution of the `request` at the [`BlockId`].
	fn estimate_gas_at(
	&self,
	request: TransactionRequest,
	at: BlockId,
	state_override: Option<StateOverride>,
	) -> impl Future<Output = Result<U256, Self::Error>> + Send
	where
	Self: LoadPendingBlock,
	{
	async move {
	let (cfg, block_env, at) = self.evm_env_at(at).await?;
	self.spawn_blocking_io(move |this| {
	let state = this.state_at_block_id(at)?;
	this.estimate_gas_with(cfg, block_env, request, state, state_override)
	})
	.await
	}
	}

Additional context

No response