Issue 462/revisit service api (core) design in 0.3 milestone#6 extensions as breadcrumbs (#723)

Author: soundofspace

examples/http_connect_proxy.rs

@@ -269,7 +269,10 @@ impl UsernameLabelParser for PriorityUsernameLabelParser {
     }
 
     fn build(self, ext: &mut Extensions) -> Result<(), Self::Error> {
-        ext.maybe_insert(self.priority);
+        if let Some(priority) = self.priority {
+            ext.insert(priority);
+        }
+
         Ok(())
     }
 }

examples/socks5_connect_proxy_over_tls.rs

@@ -22,7 +22,7 @@
 
 use rama::{
     Service,
-    extensions::ExtensionsMut,
+    extensions::{ExtensionsMut, ExtensionsRef},
     http::{
         Body, BodyExtractExt, Request, client::HttpConnector, server::HttpServer,
         service::web::Router,
@@ -100,13 +100,16 @@ async fn main() {
     });
 
     let EstablishedClientConnection {
-        req,
+        mut req,
         conn: http_service,
     } = client
         .connect(request)
         .await
         .expect("establish a proxied connection ready to make http requests");
 
+    req.extensions_mut()
+        .extend(http_service.extensions().clone());
+
     tracing::info!(
         url.full = %uri,
         "try to make GET http request and try to receive response text",