Add custom message when terminating a connection

[Javier-Novales]

Add support for providing a custom message when terminating a connection

This allows for clients to get customized messages when connections are terminated early.

[github-actions]

PR Health

Breaking changes ✔️

Package	Change	Current Version	New Version	Needed Version	Looking good?
http2	Non-Breaking	2.3.1	3.0.0	2.4.0	✔️

Changelog Entry ✔️

Package	Changed Files

Changes to files need to be accounted for in their respective changelogs.

Coverage ✔️

File	Coverage
pkgs/http2/lib/src/connection.dart	💚 83 %
pkgs/http2/lib/transport.dart	💚 82 %

This check for test coverage is informational (issues shown here will not fail the PR).

API leaks ✔️

The following packages contain symbols visible in the public API, but not exported by the library. Export these symbols or remove them from your publicly visible API.

Package	Leaked API symbols

License Headers ✔️

// Copyright (c) 2025, 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.

Files
no missing headers

All source files should start with a license header.

Unrelated files missing license headers

Files
pkgs/http/example/main.dart

[brianquinlan]

Is it possible to write tests for this?

[brianquinlan]

Since this class is not final, changing the signature of this method is probably breaking. I don't know how important that is.

[mosuem]

Filed bmw-tech/dart_apitool#207 - I do believe this is a breaking change, so this requires a version rev to 3.0.0. We should use that opportunity to do some changes like revving the minimum SDK version.

[mosuem]

As this is a breaking change, we have to update the major version number according to https://semver.org/spec/v2.0.0-rc.1.html. If we do that, we might do some other major version changes to go with it.

So I filed #1745 which will upgrade the used version of the Dart SDK and set the new version to 3.0.0-wip. Once that is landed, you should git rebase master your PR and replace 3.0.0-wip with 3.0.0 both in the pubspec.yaml and the CHANGELOG.md. This will enable us to publish the new version.

[github-actions]

Package publishing

Package	Version	Status	Publish tag (post-merge)
package:cronet_http	1.3.3	already published at pub.dev
package:cupertino_http	2.1.0	already published at pub.dev
package:http	1.4.0-wip	WIP (no publish necessary)
package:http2	3.0.0	ready to publish	http2-v3.0.0
package:http_multi_server	3.2.2	already published at pub.dev
package:http_parser	4.1.2	already published at pub.dev
package:http_profile	0.1.1-wip	WIP (no publish necessary)
package:ok_http	0.1.1-wip	WIP (no publish necessary)
package:web_socket	0.1.6	already published at pub.dev
package:web_socket_channel	3.0.2	already published at pub.dev

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.