Add HTTP Upgrade support to Response. (#1376)

tests/upgrade.rs

@@ -0,0 +1,51 @@
+#![cfg(not(target_arch = "wasm32"))]
+mod support;
+use support::*;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+
+#[tokio::test]
+async fn http_upgrade() {
+    let server = server::http(move |req| {
+        assert_eq!(req.method(), "GET");
+        assert_eq!(req.headers()["connection"], "upgrade");
+        assert_eq!(req.headers()["upgrade"], "foobar");
+
+        tokio::spawn(async move {
+            let mut upgraded = hyper::upgrade::on(req).await.unwrap();
+
+            let mut buf = vec![0; 7];
+            upgraded.read_exact(&mut buf).await.unwrap();
+            assert_eq!(buf, b"foo=bar");
+
+            upgraded.write_all(b"bar=foo").await.unwrap();
+        });
+
+        async {
+            http::Response::builder()
+                .status(http::StatusCode::SWITCHING_PROTOCOLS)
+                .header(http::header::CONNECTION, "upgrade")
+                .header(http::header::UPGRADE, "foobar")
+                .body(hyper::Body::empty())
+                .unwrap()
+        }
+    });
+
+    let res = reqwest::Client::builder()
+        .build()
+        .unwrap()
+        .get(format!("http://{}", server.addr()))
+        .header(http::header::CONNECTION, "upgrade")
+        .header(http::header::UPGRADE, "foobar")
+        .send()
+        .await
+        .unwrap();
+
+    assert_eq!(res.status(), http::StatusCode::SWITCHING_PROTOCOLS);
+    let mut upgraded = res.upgrade().await.unwrap();
+
+    upgraded.write_all(b"foo=bar").await.unwrap();
+
+    let mut buf = vec![];
+    upgraded.read_to_end(&mut buf).await.unwrap();
+    assert_eq!(buf, b"bar=foo");
+}