feat(client,server): remove tcp feature and code (#2929)

This removes the `tcp` feature from hyper's `Cargo.toml`, and the code it enabled:

- `HttpConnector`
- `GaiResolver`
- `AddrStream`

And parts of `Client` and `Server` that used those types. Alternatives will be available in the `hyper-util` crate.

Closes #2856 
Co-authored-by: MrGunflame <mrgunflame@protonmail.com>

examples/state.rs

@@ -1,52 +1,46 @@
 #![deny(warnings)]
 
+use std::net::SocketAddr;
 use std::sync::{
     atomic::{AtomicUsize, Ordering},
     Arc,
 };
 
-use hyper::service::{make_service_fn, service_fn};
-use hyper::{Body, Error, Response, Server};
+use hyper::{server::conn::Http, service::service_fn};
+use hyper::{Body, Error, Response};
+use tokio::net::TcpListener;
 
 #[tokio::main]
-async fn main() {
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
     pretty_env_logger::init();
 
-    let addr = ([127, 0, 0, 1], 3000).into();
+    let addr: SocketAddr = ([127, 0, 0, 1], 3000).into();
 
     // For the most basic of state, we just share a counter, that increments
     // with each request, and we send its value back in the response.
     let counter = Arc::new(AtomicUsize::new(0));
 
-    // The closure inside `make_service_fn` is run for each connection,
-    // creating a 'service' to handle requests for that specific connection.
-    let make_service = make_service_fn(move |_| {
-        // While the state was moved into the make_service closure,
-        // we need to clone it here because this closure is called
-        // once for every connection.
-        //
+    let listener = TcpListener::bind(addr).await?;
+    println!("Listening on http://{}", addr);
+    loop {
+        let (stream, _) = listener.accept().await?;
+
         // Each connection could send multiple requests, so
         // the `Service` needs a clone to handle later requests.
         let counter = counter.clone();
 
-        async move {
-            // This is the `Service` that will handle the connection.
-            // `service_fn` is a helper to convert a function that
-            // returns a Response into a `Service`.
-            Ok::<_, Error>(service_fn(move |_req| {
-                // Get the current count, and also increment by 1, in a single
-                // atomic operation.
-                let count = counter.fetch_add(1, Ordering::AcqRel);
-                async move { Ok::<_, Error>(Response::new(Body::from(format!("Request #{}", count)))) }
-            }))
+        // This is the `Service` that will handle the connection.
+        // `service_fn` is a helper to convert a function that
+        // returns a Response into a `Service`.
+        let service = service_fn(move |_req| {
+            // Get the current count, and also increment by 1, in a single
+            // atomic operation.
+            let count = counter.fetch_add(1, Ordering::AcqRel);
+            async move { Ok::<_, Error>(Response::new(Body::from(format!("Request #{}", count)))) }
+        });
+
+        if let Err(err) = Http::new().serve_connection(stream, service).await {
+            println!("Error serving connection: {:?}", err);
         }
-    });
-
-    let server = Server::bind(&addr).serve(make_service);
-
-    println!("Listening on http://{}", addr);
-
-    if let Err(e) = server.await {
-        eprintln!("server error: {}", e);
     }
 }