fix concurrency bug by locking cout

[NaN-git]

Output lines of differents thread can be intertwined. Granting mutual access to std::cout fixes this.

[Mic92]

@mergify queue

[mergify]

queue

🛑 The pull request has been removed from the queue default

Pull request #351 has been dequeued by a dequeue command.

You can take a look at Queue: Embarked in merge queue check runs for more details.

In case of a failure due to a flaky test, you should first retrigger the CI.
Then, re-embark the pull request into the merge queue by posting the comment
@mergifyio refresh on the pull request.

[Mic92]

@mergify dequeue

[mergify]

This pull request has been removed from the queue for the following reason: pull request dequeued.

Pull request #351 has been dequeued by a dequeue command

You should look at the reason for the failure and decide if the pull request needs to be fixed or if you want to requeue it.

If you want to requeue this pull request, you need to post a comment with the text: @mergifyio requeue

[mergify]

dequeue

✅ The pull request has been removed from the queue default

[Ericson2314]

Thanks @NaN-git!