Function map_retained 

pub fn map_retained(
    body: &[u8],
    attempt_id: &str,
    declared: OutputKind,
) -> Option<RawOutput>

Re-run this client’s mapping offline over retained response bytes (3.9.4): the output supplied for attempt_id, when the response carried one of the declared kind, else None. This checks the mapping, not the model; it makes no remote call.