You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: bench.rs
    path of file: ./repos/quinn/quinn/benches
    
    the code of the file until where you have to start completion: use std::{
    net::{IpAddr, Ipv6Addr, SocketAddr, UdpSocket},
    sync::Arc,
    thread,
};

use bencher::{benchmark_group, benchmark_main, Bencher};
use tokio::runtime::{Builder, Runtime};
use tracing::error_span;
use tracing_futures::Instrument as _;

u
    
    fn new() -> Self {
        let cert = rcgen::generate_simple_self_signed(vec!["localhost".into()]).unwrap();
        let key = rustls::PrivateKey(cert.serialize_private_key_der());
        let cert = rustls::Certificate(cert.serialize_der().unwrap());

        let mut server_config =
            quinn::ServerConfig::with_single_cert(vec![cert.clone()], key).unwrap();
        let transport_config = Arc::get_mut(&mut server_config.transport).unwrap();
        transport_config.max_concurrent_uni_streams(1024_u16.into());

        let mut roots = rustls::RootCertStore::empty();
        roots.add(&cert).unwrap();

        let client_config = quinn::ClientConfig::with_root_certificates(roots);
        Self {
            server_config,
            client_config,
        }
    }