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/client_json.rs

@@ -1,9 +1,10 @@
 #![deny(warnings)]
 #![warn(rust_2018_idioms)]
 
-use hyper::body::Buf;
-use hyper::Client;
+use hyper::Body;
+use hyper::{body::Buf, Request};
 use serde::Deserialize;
+use tokio::net::TcpStream;
 
 // A simple type alias so as to DRY.
 type Result<T> = std::result::Result<T, Box<dyn std::error::Error + Send + Sync>>;
@@ -22,10 +23,22 @@ async fn main() -> Result<()> {
 }
 
 async fn fetch_json(url: hyper::Uri) -> Result<Vec<User>> {
-    let client = Client::new();
+    let host = url.host().expect("uri has no host");
+    let port = url.port_u16().unwrap_or(80);
+    let addr = format!("{}:{}", host, port);
+
+    let stream = TcpStream::connect(addr).await?;
+
+    let (mut sender, conn) = hyper::client::conn::handshake(stream).await?;
+    tokio::task::spawn(async move {
+        if let Err(err) = conn.await {
+            println!("Connection failed: {:?}", err);
+        }
+    });
 
     // Fetch the url...
-    let res = client.get(url).await?;
+    let req = Request::builder().uri(url).body(Body::empty()).unwrap();
+    let res = sender.send_request(req).await?;
 
     // asynchronously aggregate the chunks of the body
     let body = hyper::body::aggregate(res).await?;