Function disperse_payload 

pub fn disperse_payload<T, S>(
    dispersal: Dispersal<T>,
    view: ViewNumber,
    epoch: EpochNumber,
    payload_commitment: VidCommitment2,
    public_key: &T::SignatureKey,
    private_key: &<T::SignatureKey as SignatureKey>::PrivateKey,
    tracer: Option<&LeaderTracerHandle>,
    send: S,
) -> Result<(), VidDisperseError>
where
    T: NodeType,
    S: Fn(&T::SignatureKey, &Message<T, Validated>) -> Result<(), NetworkError> + Clone + Send,

Signs a block’s dispersal and hands every recipient’s fragment of each bucket of namespaces to send, which the disperser points at the network. A Dispersal::Encode is erasure-coded bucket by bucket first. The block_build bench in espresso-types passes a send that only serializes; the spans time each step.