fix: close ListenManual subscriptions after State.dispose()

[nawafalomari]

This PR fixes the bug mentioned in this issue #1889 by closing the ListenManual after calling dispose().

[rrousselGit]

Could you fix the CI and add tests?

[nawafalomari]

Could you fix the CI and add tests?

Sure, I'm on it 👍🏻

[codecov]

Codecov Report

Merging #1980 (1b3780c) into master (97e28b6) will not change coverage.
The diff coverage is n/a.

❗ Current head 1b3780c differs from pull request most recent head 7fd6da8. Consider uploading reports for the commit 7fd6da8 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1980   +/-   ##
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  Coverage   96.22%   96.22%           
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  Files          48       48           
  Lines        2013     2013           
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  Hits         1937     1937           
  Misses         76       76           

[nawafalomari]

@rrousselGit I fixed the formatter CI issue, but I'm not quit sure how to test that the subscription is been closed after dispose is called. There is a test now to check that it is closed on dispose. Do you have any ideas?

[rrousselGit]

The goal of that issue is to be able to call subscription.read() within dispose overrides.
You could do that in a test.

class A extends ConsumerState<...> {
  late final sub = ref.listen(provider, (prev, next) {});
  
  void dispose() {
    sub.read().doSomething();
    super.dispose();
  } 
}