fix: 1. use returned instance for modifyResponse as well; 2. remove mandatory copyWith parameters.

@@ -196,9 +196,10 @@ class GetHttpClient {
 
       var response = await _httpClient.send<T>(newRequest);
 
-      await _modifier.modifyResponse(newRequest, response);
+      final newResponse =
+          await _modifier.modifyResponse<T>(newRequest, response);
 
-      if (HttpStatus.unauthorized == response.statusCode &&
+      if (HttpStatus.unauthorized == newResponse.statusCode &&
           _modifier.authenticator != null &&
           requestNumber <= maxAuthRetries) {
         return _performRequest<T>(
@@ -207,23 +208,23 @@ class GetHttpClient {
           requestNumber: requestNumber + 1,
           headers: newRequest.headers,
         );
-      } else if (HttpStatus.unauthorized == response.statusCode) {
+      } else if (HttpStatus.unauthorized == newResponse.statusCode) {
         if (!errorSafety) {
           throw UnauthorizedException();
         } else {
           return Response<T>(
             request: newRequest,
-            headers: response.headers,
-            statusCode: response.statusCode,
-            body: response.body,
-            bodyBytes: response.bodyBytes,
-            bodyString: response.bodyString,
-            statusText: response.statusText,
+            headers: newResponse.headers,
+            statusCode: newResponse.statusCode,
+            body: newResponse.body,
+            bodyBytes: newResponse.bodyBytes,
+            bodyString: newResponse.bodyString,
+            statusText: newResponse.statusText,
           );
         }
       }
 
-      return response;
+      return newResponse;
     } on Exception catch (err) {
       if (!errorSafety) {
         throw GetHttpException(err.toString());

@@ -42,11 +42,15 @@ class GetModifier<T> {
     return newRequest;
   }
 
-  Future<void> modifyResponse(Request request, Response response) async {
+  Future<Response<T>> modifyResponse<T>(
+      Request<T> request, Response<T> response) async {
+    var newResponse = response;
     if (_responseModifiers.isNotEmpty) {
       for (var interceptor in _responseModifiers) {
-        await interceptor(request, response);
+        newResponse = await interceptor(request, response) as Response<T>;
       }
     }
+
+    return newResponse;
   }
 }

@@ -76,9 +76,9 @@ class Request<T> {
   }
 
   Request copyWith({
-    required Uri url,
-    required String method,
-    required Map<String, String> headers,
+    Uri? url,
+    String? method,
+    Map<String, String>? headers,
     Stream<List<int>>? bodyBytes,
     bool followRedirects = true,
     int maxRedirects = 4,
@@ -91,10 +91,10 @@ class Request<T> {
       assert(maxRedirects > 0);
     }
     return Request._(
-      url: url,
-      method: method,
+      url: url ?? this.url,
+      method: method ?? this.method,
       bodyBytes: bodyBytes ??= BodyBytesStream.fromBytes(const []),
-      headers: Map.from(headers),
+      headers: headers == null ? this.headers : Map.from(headers),
       followRedirects: followRedirects,
       maxRedirects: maxRedirects,
       contentLength: contentLength,