Add support for stop(cause:).

[ioquatix]

Add cause: to Async::Task#stop(cause:) so that extra information about the reason for stopping can be provided. It must be an exception suitable for raise Async::Stop, cause: cause.

Types of Changes

• New feature.

Contribution

• I added tests for my changes.
• I tested my changes locally.
• I agree to the Developer's Certificate of Origin 1.1.

[ioquatix]

I found an issue, Fiber#raise does not seem to support cause: keyword argument correctly. I need to investigate.

[macournoyer]

I test w/ a sleep, and sending SIGINT to the worker sleeping. Here's what I got:

Async::Stop: {cause: #<Async::Stop: {cause: #<Async::Stop: {cause: #<Async::Stop: {cause: #<Interrupt: Interrupt>}>}>}>}
/Users/ma/.gem/ruby/3.4.4/bundler/gems/async-53670d16cb43/lib/async/scheduler.rb:221:in 'IO::Event::Selector::KQueue#transfer'
	/Users/ma/.gem/ruby/3.4.4/bundler/gems/async-53670d16cb43/lib/async/scheduler.rb:221:in 'Async::Scheduler#block'
	/Users/ma/.gem/ruby/3.4.4/bundler/gems/async-53670d16cb43/lib/async/scheduler.rb:254:in 'Async::Scheduler#kernel_sleep'

Seems there is too much nesting.

[ioquatix]

Two issues:

• https://bugs.ruby-lang.org/issues/21359
• https://bugs.ruby-lang.org/issues/21360