Function listen 

pub fn listen<S, M>(
    sockets: impl IntoIterator<Item = S>,
    params: ConnectionParams<'_>,
    cid_generator: impl ConnectionIdGenerator<'static> + Clone,
    metrics: M,
) -> Result<Vec<QuicConnectionStream<M>>>
where
    S: TryInto<QuicListener, Error = Error>,
    M: Metrics,

Starts listening for inbound QUIC connections on the given sockets.

Each socket is converted into a QuicListener with defaulted socket parameters. The listeners are then passed to listen_with_capabilities.