feat(http): add new middleware feature

packages/wyatt_http_client/lib/src/middleware.dart

@@ -14,31 +14,25 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-part of 'pipeline.dart';
+import 'package:wyatt_http_client/src/models/middleware_context.dart';
+import 'package:wyatt_http_client/src/models/middleware_request.dart';
+import 'package:wyatt_http_client/src/models/middleware_response.dart';
 
-class Middleware {
-  /// The http [MiddlewareClient] used by this [Middleware]
-  MiddlewareClient? _client;
+abstract class Middleware {
+  Middleware();
+  String getName();
+}
 
-  String getName() => 'MiddlewareNode';
-
-  // ignore: avoid_setters_without_getters
-  set httpClient(MiddlewareClient? client) => _client = client;
-
-  Client? get client => _client?.inner;
-
+mixin OnRequestMiddleware {
   Future<MiddlewareRequest> onRequest(
+    MiddlewareContext context,
     MiddlewareRequest request,
-  ) async {
-    return request;
-  }
-
-  Future<MiddlewareResponse> onResponse(MiddlewareResponse response) async {
-    return response;
-  }
+  );
+}
 
-  @override
-  String toString() {
-    return getName();
-  }
+mixin OnResponseMiddleware {
+  Future<MiddlewareResponse> onResponse(
+    MiddlewareContext context,
+    MiddlewareResponse response,
+  );
 }