Function drive_with_payloads_mut 

pub async fn drive_with_payloads_mut<S, C, E>(
    app: &mut WireframeApp<S, C, E>,
    payloads: Vec<Vec<u8>>,
) -> Result<Vec<u8>>
where
    S: TestSerializer,
    C: Send + 'static,
    E: Packet,

Encode payloads as length-delimited frames and drive a mutable app.

let mut app = WireframeApp::new().expect("failed to initialize app");
let out = drive_with_payloads_mut(&mut app, vec![vec![1], vec![2]]).await?;