Function call_forkchoice_updated_with_reth 

pub(crate) async fn call_forkchoice_updated_with_reth<N: Network, P: Provider<N> + EngineApiValidWaitExt<N>>(
    provider: P,
    message_version: Option<EngineApiMessageVersion>,
    forkchoice_state: ForkchoiceState,
) -> TransportResult<ForkchoiceUpdated>

Calls either reth_forkchoiceUpdated or the standard engine_forkchoiceUpdated* depending on use_reth.

When use_reth is true, uses the reth_forkchoiceUpdated endpoint which sends a regular FCU with no payload attributes.