Function aggregate 

pub fn aggregate(results: &[Relayed], policy: AggregatePolicy) -> StatusCode

Available on crate feature hub only.

Turns the results of a fan-out into the status code the sender is told.

A broadcast that reached nobody is 4003 Connection problem; one where a party rejected the object surfaces that party’s own code, because the sender needs to see it.

Spec: 2.3.0 §status_codes_4xxx_hub_errors