Function pinned_client 

pub async fn pinned_client(
    url: &Url,
    private: PrivateAddresses,
) -> Result<Client, AddressError>

A client for url: its host resolved once through resolve_public, pinned to what it resolved to so the connection cannot land elsewhere, and following no redirect, which would land it elsewhere all the same.

A URL whose host is already a literal address has nothing to pin – there is no name, so nothing can answer differently the second time.