Fixed keep-alive on response example (#316)

* fixed keep-alive on response example

* fixed dead code and unused variable errors

docs/server.md

@@ -97,6 +97,7 @@ Actix Web keeps connections open to wait for subsequent requests.
 If the first option above is selected, then keep-alive is enabled for HTTP/1.1 requests if the response does not explicitly disallow it by, for example, setting the [connection type][httpconnectiontype] to `Close` or `Upgrade`. Force closing a connection can be done with [the `force_close()` method on `HttpResponseBuilder`](https://docs.rs/actix-web/4/actix_web/struct.HttpResponseBuilder.html#method.force_close)
 
 > Keep-alive is **off** for HTTP/1.0 and is **on** for HTTP/1.1 and HTTP/2.0.
+
 <CodeBlock example="server" file="keep_alive_tp.rs" section="example" />
 
 ## Graceful shutdown

examples/server/src/keep_alive_tp.rs

@@ -1,11 +1,17 @@
+#![allow(dead_code)]
+
 // <example>
 use actix_web::{http, HttpRequest, HttpResponse};
 
-async fn index(req: HttpRequest) -> HttpResponse {
+async fn index(_req: HttpRequest) -> HttpResponse {
-    HttpResponse::Ok()
+    let mut resp = HttpResponse::Ok()
-        .connection_type(http::ConnectionType::Close) // <- Close connection
+        .force_close() // <- Close connection on HttpResponseBuilder
-        .force_close() // <- Alternative method
+        .finish();
-        .finish()
+
+    // Alternatively close connection on the HttpResponse struct
+    resp.head_mut().set_connection_type(http::ConnectionType::Close);
+
+    resp
 }
 // </example>
 

examples/server/src/main.rs

@@ -1,4 +1,5 @@
 pub mod keep_alive;
+pub mod keep_alive_tp;
 pub mod signals;
 pub mod ssl;
 pub mod workers;