Add a simple example to test against Cloudflare's 0-rtt server implementation

Cargo.toml

@@ -59,3 +59,8 @@ path = "examples/tlsserver.rs"
 [[example]]
 name = "simpleclient"
 path = "examples/simpleclient.rs"
+
+[[example]]
+name = "simple_0rtt_client"
+path = "examples/simple_0rtt_client.rs"
+required-features = ["logging"]

examples/simple_0rtt_client.rs

@@ -0,0 +1,42 @@
+use std::sync::Arc;
+
+use std::io::{stdout, Read, Write};
+use std::net::TcpStream;
+
+extern crate rustls;
+extern crate webpki;
+extern crate webpki_roots;
+extern crate env_logger;
+
+fn start_session(config: &Arc<rustls::ClientConfig>, domain_name: &str) {
+    let dns_name = webpki::DNSNameRef::try_from_ascii_str(domain_name).unwrap();
+    let mut sess = rustls::ClientSession::new(config, dns_name);
+    let mut sock = TcpStream::connect(format!("{}:443", domain_name)).unwrap();
+    sock.set_nodelay(true).unwrap();
+    let mut stream = rustls::Stream::new(&mut sess, &mut sock);
+    let request = format!(
+        "GET / HTTP/1.1\r\n\
+         Host: {}\r\n\
+         Connection: close\r\n\
+         Accept-Encoding: identity\r\n\
+         \r\n",
+        domain_name
+    );
+
+    stream.write_all(request.as_bytes()).unwrap();
+    let mut plaintext = Vec::new();
+    stream.read_to_end(&mut plaintext).unwrap();
+    stdout().write_all(&plaintext).unwrap();
+}
+
+fn main() {
+    env_logger::init();
+    let mut config = rustls::ClientConfig::new();
+    config.enable_early_data = true;
+    config
+        .root_store
+        .add_server_trust_anchors(&webpki_roots::TLS_SERVER_ROOTS);
+    let config = Arc::new(config);
+    start_session(&config, "mesalink.io");
+    start_session(&config, "mesalink.io");
+}