Function build_sign 

pub(super) fn build_sign<Rng: RngCore + CryptoRng, KeyRng: RngCore + EntropicRng, R: Runtime>(
    keymgr: &Arc<KeyMgr>,
    pow_manager: &Arc<PowManagerGeneric<R, RendRequest>>,
    config: &Arc<OnionServiceConfigPublisherView>,
    authorized_clients: Option<&BTreeMap<HsClientNickname, HsClientDescEncKey>>,
    ipt_set: &IptSet,
    period: TimePeriod,
    revision_counter: RevisionCounter,
    rng: &mut Rng,
    key_rng: &mut KeyRng,
    now: SystemTime,
    max_hsdesc_len: usize,
) -> Result<VersionedDescriptor, FatalError>

Build the descriptor.

The now argument is used for computing the expiry of the intro_{auth, enc}_key_cert certificates included in the descriptor. The expiry will be set to 54 hours from now.

Note: blind_id_kp is the blinded hidden service signing keypair used to sign descriptor signing keys (KP_hs_blind_id, KS_hs_blind_id).