Function get_namespace_proof_range 

async fn get_namespace_proof_range<State>(
    state: &State,
    start: usize,
    end: usize,
    namespace: u64,
    fetch_timeout: Duration,
    large_object_range_limit: usize,
) -> Result<Vec<NamespaceProof>, Error>
where
    State: AvailabilityDataSource<SeqTypes>,