Function init_finalized_blocks 

pub(crate) async fn init_finalized_blocks<TContext, P>(
    context: &TContext,
    partition_prefix: &str,
    page_cache: CacheRef,
    provider: P,
    retention_blocks: u64,
) -> Result<Hybrid<TContext, P>>
where
    TContext: Clock + Metrics + Spawner + Storage + BufferPooler + Clone + Send + 'static,
    P: FinalizedBlocksProvider + 'static,

Initialize the Hybrid finalized blocks store backed by a prunable archive (for retention_blocks recent items) and a reth provider lookup (for everything older).