chore: checkpoint before Python removal

vendor/quinn/examples/single_socket.rs

@@ -0,0 +1,65 @@
+//! This example demonstrates how to make multiple outgoing connections on a single UDP socket.
+//!
+//! Checkout the `README.md` for guidance.
+
+use std::{
+    error::Error,
+    net::{IpAddr, Ipv4Addr, SocketAddr},
+};
+
+use quinn::Endpoint;
+
+mod common;
+use common::{make_client_endpoint, make_server_endpoint};
+use rustls::pki_types::CertificateDer;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error + Send + Sync + 'static>> {
+    let addr1 = SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 5000);
+    let addr2 = SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 5001);
+    let addr3 = SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 5002);
+    let server1_cert = run_server(addr1)?;
+    let server2_cert = run_server(addr2)?;
+    let server3_cert = run_server(addr3)?;
+
+    let client = make_client_endpoint(
+        SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 0),
+        &[&server1_cert, &server2_cert, &server3_cert],
+    )?;
+
+    // connect to multiple endpoints using the same socket/endpoint
+    tokio::join!(
+        run_client(&client, addr1),
+        run_client(&client, addr2),
+        run_client(&client, addr3),
+    );
+
+    // Make sure the server has a chance to clean up
+    client.wait_idle().await;
+
+    Ok(())
+}
+
+/// Runs a QUIC server bound to given address and returns server certificate.
+fn run_server(
+    addr: SocketAddr,
+) -> Result<CertificateDer<'static>, Box<dyn Error + Send + Sync + 'static>> {
+    let (endpoint, server_cert) = make_server_endpoint(addr)?;
+    // accept a single connection
+    tokio::spawn(async move {
+        let connection = endpoint.accept().await.unwrap().await.unwrap();
+        println!(
+            "[server] incoming connection: addr={}",
+            connection.remote_address()
+        );
+    });
+
+    Ok(server_cert)
+}
+
+/// Attempt QUIC connection with the given server address.
+async fn run_client(endpoint: &Endpoint, server_addr: SocketAddr) {
+    let connect = endpoint.connect(server_addr, "localhost").unwrap();
+    let connection = connect.await.unwrap();
+    println!("[client] connected: addr={}", connection.remote_address());
+}