diff --git a/pkgs/cupertino_http/example/integration_test/client_profile_test.dart b/pkgs/cupertino_http/example/integration_test/client_profile_test.dart
new file mode 100644
index 0000000000..e28a96a323
--- /dev/null
+++ b/pkgs/cupertino_http/example/integration_test/client_profile_test.dart
@@ -0,0 +1,266 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:cupertino_http/src/cupertino_client.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:http/http.dart';
+import 'package:http_profile/http_profile.dart';
+import 'package:integration_test/integration_test.dart';
+
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  group('profile', () {
+    HttpClientRequestProfile.profilingEnabled = true;
+
+    group('non-streamed POST', () {
+      late HttpServer successServer;
+      late Uri successServerUri;
+      late HttpClientRequestProfile profile;
+
+      setUpAll(() async {
+        successServer = (await HttpServer.bind('localhost', 0))
+          ..listen((request) async {
+            await request.drain<void>();
+            request.response.headers.set('Content-Type', 'text/plain');
+            request.response.headers.set('Content-Length', '11');
+            request.response.write('Hello World');
+            await request.response.close();
+          });
+        successServerUri = Uri.http('localhost:${successServer.port}');
+        final client = CupertinoClientWithProfile.defaultSessionConfiguration();
+        await client.post(successServerUri,
+            headers: {'Content-Type': 'text/plain'}, body: 'Hi');
+        await Future<void>.delayed(const Duration(seconds: 1));
+        profile = client.profile!;
+      });
+      tearDownAll(() {
+        successServer.close();
+      });
+
+      test('profile attributes', () {
+        expect(profile.events, isEmpty);
+        expect(profile.requestMethod, 'POST');
+        expect(profile.requestUri, successServerUri.toString());
+      });
+
+      test('request attributes', () {
+        expect(profile.requestData.bodyBytes, 'Hi'.codeUnits);
+        expect(profile.requestData.connectionInfo,
+            containsPair('package', 'package:cupertino_http'));
+        expect(profile.requestData.contentLength, 2);
+        expect(profile.requestData.endTime, isNotNull);
+        expect(profile.requestData.error, isNull);
+        // XXX Should 'content-length' also be in the headers? It is not for the
+        // request but it is for the response.
+        expect(profile.requestData.headers,
+            containsPair('Content-Type', ['text/plain; charset=utf-8']));
+        expect(profile.requestData.persistentConnection, isNull);
+        expect(profile.requestData.proxyDetails, isNull);
+        expect(profile.requestData.startTime, isNotNull);
+      });
+
+      test('response attributes', () {
+        expect(profile.responseData.bodyBytes, 'Hello World'.codeUnits);
+        expect(profile.responseData.compressionState, isNull);
+        // XXX how are request and response connectionInfo supposed to be
+        // different?
+        expect(profile.responseData.connectionInfo, isNull);
+        expect(profile.responseData.contentLength, 11);
+        expect(profile.responseData.endTime, isNotNull);
+        expect(profile.responseData.error, isNull);
+        expect(profile.responseData.headers,
+            containsPair('content-type', ['text/plain']));
+        expect(profile.responseData.headers,
+            containsPair('content-length', ['11']));
+        expect(profile.responseData.isRedirect, false);
+        expect(profile.responseData.persistentConnection, isNull);
+        expect(profile.responseData.reasonPhrase, 'OK');
+        expect(profile.responseData.redirects, isEmpty);
+        expect(profile.responseData.startTime, isNotNull);
+        expect(profile.responseData.statusCode, 200);
+      });
+    });
+
+    group('streaming POST request', () {
+      late HttpServer successServer;
+      late Uri successServerUri;
+      late HttpClientRequestProfile profile;
+
+      setUpAll(() async {
+        successServer = (await HttpServer.bind('localhost', 0))
+          ..listen((request) async {
+            await request.drain<void>();
+            request.response.headers.set('Content-Type', 'text/plain');
+            request.response.headers.set('Content-Length', '11');
+            request.response.write('Hello World');
+            await request.response.close();
+          });
+        successServerUri = Uri.http('localhost:${successServer.port}');
+        final client = CupertinoClientWithProfile.defaultSessionConfiguration();
+        final request = StreamedRequest('POST', successServerUri);
+        final stream = () async* {
+          for (var i = 0; i < 1000; ++i) {
+            await Future<void>.delayed(const Duration());
+            // The request has started but not finished.
+            expect(client.profile!.requestData.startTime, isNotNull);
+            expect(client.profile!.requestData.endTime, isNull);
+            expect(client.profile!.responseData.startTime, isNull);
+            expect(client.profile!.responseData.endTime, isNull);
+            yield 'Hello'.codeUnits;
+          }
+        }();
+        unawaited(
+            request.sink.addStream(stream).then((_) => request.sink.close()));
+
+        await client.send(request);
+        profile = client.profile!;
+      });
+      tearDownAll(() {
+        successServer.close();
+      });
+
+      test('request attributes', () async {
+        expect(profile.requestData.bodyBytes, ('Hello' * 1000).codeUnits);
+        expect(profile.requestData.contentLength, isNull);
+        expect(profile.requestData.endTime, isNotNull);
+        expect(profile.requestData.startTime, isNotNull);
+      });
+    });
+
+    group('failed POST request', () {
+      late HttpClientRequestProfile profile;
+
+      setUpAll(() async {
+        final client = CupertinoClientWithProfile.defaultSessionConfiguration();
+        try {
+          await client.post(Uri.http('thisisnotahost'),
+              headers: {'Content-Type': 'text/plain'}, body: 'Hi');
+          fail('expected exception');
+        } on ClientException {
+          // Expected exception.
+        }
+        profile = client.profile!;
+      });
+
+      test('profile attributes', () {
+        expect(profile.events, isEmpty);
+        expect(profile.requestMethod, 'POST');
+        expect(profile.requestUri, 'http://thisisnotahost');
+      });
+
+      test('request attributes', () {
+        expect(profile.requestData.bodyBytes, 'Hi'.codeUnits);
+        expect(profile.requestData.connectionInfo,
+            containsPair('package', 'package:cupertino_http'));
+        expect(profile.requestData.contentLength, 2);
+        expect(profile.requestData.endTime, isNotNull);
+        expect(profile.requestData.error, startsWith('ClientException:'));
+        // XXX Should 'content-length' also be in the headers? It is not for the
+        // request but it is for the response.
+        expect(profile.requestData.headers,
+            containsPair('Content-Type', ['text/plain; charset=utf-8']));
+        expect(profile.requestData.persistentConnection, isNull);
+        expect(profile.requestData.proxyDetails, isNull);
+        expect(profile.requestData.startTime, isNotNull);
+      });
+
+      test('response attributes', () {
+        // XXX is this the correct expectation? If we have a failure at request
+        // time then `responseData` should logically contain nothing because
+        // no response was received. But does `requestData.closeWithError`
+        // satisfy whatever the I/O service expects?
+        expect(profile.responseData.bodyBytes, isEmpty);
+        expect(profile.responseData.compressionState, isNull);
+        expect(profile.responseData.connectionInfo, isNull);
+        expect(profile.responseData.contentLength, isNull);
+        expect(profile.responseData.endTime, isNull);
+        expect(profile.responseData.error, isNull);
+        expect(profile.responseData.headers, isNull);
+        expect(profile.responseData.isRedirect, isNull);
+        expect(profile.responseData.persistentConnection, isNull);
+        expect(profile.responseData.reasonPhrase, isNull);
+        expect(profile.responseData.redirects, isEmpty);
+        expect(profile.responseData.startTime, isNull);
+        expect(profile.responseData.statusCode, isNull);
+      });
+    });
+
+    group('failed POST response', () {
+      late HttpServer successServer;
+      late Uri successServerUri;
+      late HttpClientRequestProfile profile;
+
+      setUpAll(() async {
+        successServer = (await HttpServer.bind('localhost', 0))
+          ..listen((request) async {
+            await request.drain<void>();
+            request.response.headers.set('Content-Type', 'text/plain');
+            request.response.headers.set('Content-Length', '11');
+            final socket = await request.response.detachSocket();
+            await socket.close();
+          });
+        successServerUri = Uri.http('localhost:${successServer.port}');
+        final client = CupertinoClientWithProfile.defaultSessionConfiguration();
+
+        try {
+          await client.post(successServerUri,
+              headers: {'Content-Type': 'text/plain'}, body: 'Hi');
+          fail('expected exception');
+        } on ClientException {
+          // Expected exception.
+        }
+        await Future<void>.delayed(const Duration(seconds: 1));
+        profile = client.profile!;
+      });
+      tearDownAll(() {
+        successServer.close();
+      });
+
+      test('profile attributes', () {
+        expect(profile.events, isEmpty);
+        expect(profile.requestMethod, 'POST');
+        expect(profile.requestUri, successServerUri.toString());
+      });
+
+      test('request attributes', () {
+        expect(profile.requestData.bodyBytes, 'Hi'.codeUnits);
+        expect(profile.requestData.connectionInfo,
+            containsPair('package', 'package:cupertino_http'));
+        expect(profile.requestData.contentLength, 2);
+        expect(profile.requestData.endTime, isNotNull);
+        expect(profile.requestData.error, isNull);
+        // XXX Should 'content-length' also be in the headers? It is not for the
+        // request but it is for the response.
+        expect(profile.requestData.headers,
+            containsPair('Content-Type', ['text/plain; charset=utf-8']));
+        expect(profile.requestData.persistentConnection, isNull);
+        expect(profile.requestData.proxyDetails, isNull);
+        expect(profile.requestData.startTime, isNotNull);
+      });
+
+      test('response attributes', () {
+        expect(profile.responseData.bodyBytes, isEmpty);
+        expect(profile.responseData.compressionState, isNull);
+        expect(profile.responseData.connectionInfo, isNull);
+        expect(profile.responseData.contentLength, 11);
+        expect(profile.responseData.endTime, isNotNull);
+        expect(profile.responseData.error, startsWith('ClientException:'));
+        expect(profile.responseData.headers,
+            containsPair('content-type', ['text/plain']));
+        expect(profile.responseData.headers,
+            containsPair('content-length', ['11']));
+        expect(profile.responseData.isRedirect, false);
+        expect(profile.responseData.persistentConnection, isNull);
+        expect(profile.responseData.reasonPhrase, 'OK');
+        expect(profile.responseData.redirects, isEmpty);
+        expect(profile.responseData.startTime, isNotNull);
+        expect(profile.responseData.statusCode, 200);
+      });
+    });
+  });
+}
diff --git a/pkgs/cupertino_http/example/integration_test/main.dart b/pkgs/cupertino_http/example/integration_test/main.dart
index 0d4d5e16d9..a632b0c40a 100644
--- a/pkgs/cupertino_http/example/integration_test/main.dart
+++ b/pkgs/cupertino_http/example/integration_test/main.dart
@@ -5,6 +5,7 @@
 import 'package:integration_test/integration_test.dart';
 
 import 'client_conformance_test.dart' as client_conformance_test;
+import 'client_profile_test.dart' as profile_test;
 import 'client_test.dart' as client_test;
 import 'data_test.dart' as data_test;
 import 'error_test.dart' as error_test;
@@ -30,6 +31,7 @@ void main() {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();
 
   client_conformance_test.main();
+  profile_test.main();
   client_test.main();
   data_test.main();
   error_test.main();
diff --git a/pkgs/cupertino_http/example/pubspec.yaml b/pkgs/cupertino_http/example/pubspec.yaml
index f394051994..c89ca4bf03 100644
--- a/pkgs/cupertino_http/example/pubspec.yaml
+++ b/pkgs/cupertino_http/example/pubspec.yaml
@@ -28,6 +28,8 @@ dev_dependencies:
     sdk: flutter
   http_client_conformance_tests:
     path: ../../http_client_conformance_tests/
+  http_profile:
+    path: ../../http_profile/
   integration_test:
     sdk: flutter
   test: ^1.21.1
diff --git a/pkgs/cupertino_http/lib/cupertino_http.dart b/pkgs/cupertino_http/lib/cupertino_http.dart
index 68691b8ab4..55d62d3c15 100644
--- a/pkgs/cupertino_http/lib/cupertino_http.dart
+++ b/pkgs/cupertino_http/lib/cupertino_http.dart
@@ -87,5 +87,5 @@ import 'package:http/http.dart';
 import 'src/cupertino_client.dart';
 
 export 'src/cupertino_api.dart';
-export 'src/cupertino_client.dart';
+export 'src/cupertino_client.dart' show CupertinoClient;
 export 'src/cupertino_web_socket.dart';
diff --git a/pkgs/cupertino_http/lib/src/cupertino_client.dart b/pkgs/cupertino_http/lib/src/cupertino_client.dart
index c29cb0a8ce..e70f9b5ecc 100644
--- a/pkgs/cupertino_http/lib/src/cupertino_client.dart
+++ b/pkgs/cupertino_http/lib/src/cupertino_client.dart
@@ -45,7 +45,6 @@ class _TaskTracker {
 
   void close() {
     responseController.close();
-    profile?.responseData.close();
   }
 }
 
@@ -77,7 +76,7 @@ class CupertinoClient extends BaseClient {
 
   URLSession? _urlSession;
 
-  CupertinoClient._(URLSession urlSession) : _urlSession = urlSession;
+  CupertinoClient._(this._urlSession);
 
   String? _findReasonPhrase(int statusCode) {
     switch (statusCode) {
@@ -174,14 +173,28 @@ class CupertinoClient extends BaseClient {
     if (error != null) {
       final exception = ClientException(
           error.localizedDescription ?? 'Unknown', taskTracker.request.url);
+      if (taskTracker.profile != null &&
+          taskTracker.profile!.requestData.endTime == null) {
+        // Error occurred during the request.
+        taskTracker.profile!.requestData.closeWithError(exception.toString());
+      } else {
+        // Error occurred during the response.
+        taskTracker.profile?.responseData.closeWithError(exception.toString());
+      }
       if (taskTracker.responseCompleter.isCompleted) {
         taskTracker.responseController.addError(exception);
       } else {
         taskTracker.responseCompleter.completeError(exception);
       }
-    } else if (!taskTracker.responseCompleter.isCompleted) {
-      taskTracker.responseCompleter.completeError(
-          StateError('task completed without an error or response'));
+    } else {
+      assert(taskTracker.profile == null ||
+          taskTracker.profile!.requestData.endTime != null);
+
+      taskTracker.profile?.responseData.close();
+      if (!taskTracker.responseCompleter.isCompleted) {
+        taskTracker.responseCompleter.completeError(
+            StateError('task completed without an error or response'));
+      }
     }
     taskTracker.close();
     _tasks.remove(task);
@@ -213,6 +226,8 @@ class CupertinoClient extends BaseClient {
       URLSession session, URLSessionTask task, URLResponse response) {
     final taskTracker = _tracker(task);
     taskTracker.responseCompleter.complete(response);
+    taskTracker.profile!.requestData.close();
+
     return URLSessionResponseDisposition.urlSessionResponseAllow;
   }
 
@@ -252,6 +267,12 @@ class CupertinoClient extends BaseClient {
     return (await queue.hasNext, queue.rest);
   }
 
+  HttpClientRequestProfile? _createProfile(BaseRequest request) =>
+      HttpClientRequestProfile.profile(
+          requestStartTime: DateTime.now(),
+          requestMethod: request.method,
+          requestUri: request.url.toString());
+
   @override
   Future<StreamedResponse> send(BaseRequest request) async {
     // The expected success case flow (without redirects) is:
@@ -274,10 +295,7 @@ class CupertinoClient extends BaseClient {
 
     final stream = request.finalize();
 
-    final profile = HttpClientRequestProfile.profile(
-        requestStartTime: DateTime.now(),
-        requestMethod: request.method,
-        requestUri: request.url.toString());
+    final profile = _createProfile(request);
     profile?.requestData
       ?..connectionInfo = {
         'package': 'package:cupertino_http',
@@ -297,7 +315,6 @@ class CupertinoClient extends BaseClient {
       // `httpBodyStream` requires a lot of expensive setup and data passing.
       urlRequest.httpBody = Data.fromList(request.bodyBytes);
       profile?.requestData.bodySink.add(request.bodyBytes);
-      unawaited(profile?.requestData.close());
     } else if (await _hasData(stream) case (true, final s)) {
       // If the request is supposed to be bodyless (e.g. GET requests)
       // then setting `httpBodyStream` will cause the request to fail -
@@ -307,10 +324,7 @@ class CupertinoClient extends BaseClient {
       } else {
         final splitter = StreamSplitter(s);
         urlRequest.httpBodyStream = splitter.split();
-        unawaited(
-            profile.requestData.bodySink.addStream(splitter.split()).then((e) {
-          profile.requestData.close();
-        }));
+        unawaited(profile.requestData.bodySink.addStream(splitter.split()));
       }
     }
 
@@ -324,12 +338,7 @@ class CupertinoClient extends BaseClient {
     final maxRedirects = request.followRedirects ? request.maxRedirects : 0;
 
     late URLResponse result;
-    try {
-      result = await taskTracker.responseCompleter.future;
-    } catch (e) {
-      unawaited(profile?.responseData.closeWithError(e.toString()));
-      rethrow;
-    }
+    result = await taskTracker.responseCompleter.future;
 
     final response = result as HTTPURLResponse;
 
@@ -348,9 +357,13 @@ class CupertinoClient extends BaseClient {
       );
     }
 
+    final contentLength = response.expectedContentLength == -1
+        ? null
+        : response.expectedContentLength;
     final isRedirect = !request.followRedirects && taskTracker.numRedirects > 0;
     profile?.responseData
-      ?..headersCommaValues = responseHeaders
+      ?..contentLength = contentLength
+      ..headersCommaValues = responseHeaders
       ..isRedirect = isRedirect
       ..reasonPhrase = _findReasonPhrase(response.statusCode)
       ..startTime = DateTime.now()
@@ -360,9 +373,7 @@ class CupertinoClient extends BaseClient {
       taskTracker.responseController.stream,
       response.statusCode,
       url: taskTracker.lastUrl ?? request.url,
-      contentLength: response.expectedContentLength == -1
-          ? null
-          : response.expectedContentLength,
+      contentLength: contentLength,
       reasonPhrase: _findReasonPhrase(response.statusCode),
       request: request,
       isRedirect: isRedirect,
@@ -370,3 +381,23 @@ class CupertinoClient extends BaseClient {
     );
   }
 }
+
+class CupertinoClientWithProfile extends CupertinoClient {
+  HttpClientRequestProfile? profile;
+
+  @override
+  HttpClientRequestProfile? _createProfile(BaseRequest request) =>
+      profile = super._createProfile(request);
+
+  CupertinoClientWithProfile._(super._urlSession) : super._();
+
+  factory CupertinoClientWithProfile.defaultSessionConfiguration() {
+    final config = URLSessionConfiguration.defaultSessionConfiguration();
+    final session = URLSession.sessionWithConfiguration(config,
+        onComplete: CupertinoClient._onComplete,
+        onData: CupertinoClient._onData,
+        onRedirect: CupertinoClient._onRedirect,
+        onResponse: CupertinoClient._onResponse);
+    return CupertinoClientWithProfile._(session);
+  }
+}