HttpClientRequest.abort() fails silently on web

[matteokeole]

Hi,
I'm trying to abort ongoing HTTP requests when a new route is pushed on top of the navigator route stack. However, on the web platform the abort() method on HttpClientRequest doesn't seem to cancel the request and doesn't throw.

I could reproduce the issue with the following sample:

import "dart:async";

import "package:flutter/material.dart";
import "package:universal_io/io.dart";

// Set the API URL here
const String baseUrl = "...";
const String endpoint = "...";

void main() {
  testNative();

  runApp(Container(color: Colors.black));
}

void testNative() async {
  final HttpClient client = newUniversalHttpClient();
  final Uri url = Uri.https(baseUrl, endpoint);
  final HttpClientRequest request = await client.postUrl(url);

  Timer(const Duration(milliseconds: 50), () {
    request.abort();

    debugPrint("abort");
  });

  request
      .close()
      .then(
        (_) => debugPrint("then()"),
        onError: (_) => debugPrint("onError()"),
      )
      .catchError(
        (_) => debugPrint("catchError()"),
      );
}

abort() is called before the request done future was completed, but it doesn't complete with an error.

Output of flutter doctor -v:

[✓] Flutter (Channel stable, 3.10.4, on Ubuntu 22.04.2 LTS 5.19.0-43-generic, locale en_US.UTF-8)
    • Flutter version 3.10.4 on channel stable at /home/keole/snap/flutter/common/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 682aa387cf (10 days ago), 2023-06-05 18:04:56 -0500
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      (or visit https://flutter.dev/docs/get-started/install/linux#android-setup for detailed instructions).

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[✓] Connected device (2 available)
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    • Chrome (web)    • chrome • web-javascript • Google Chrome 114.0.5735.133

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