Function resolve_endpoint 

pub(crate) async fn resolve_endpoint(
    client: &Client,
    operator_did: &str,
    private: PrivateAddresses,
) -> Result<(String, Client), ClaimFetchError>

Resolves operator_did’s document and reads its #atproto_pds endpoint out of it, on its own so one tick resolves the operator once and reads every record it needs from the same endpoint.

Answers with the endpoint and the client to read it through: one pinned to what the endpoint’s host resolved to and following no redirect. Reading through anything else would let a name that answers differently the second time, or a 3xx from the operator’s PDS, land the request at an address the check never saw.