Fix static local variable multi-threaded initialization

[678098]

Is there an existing issue for this?

• [X] I have searched the existing issues

Current Behavior

Place where the problem might occur:

https://github.com/bloomberg/blazingmq/blob/a6f119b17930c7aa5fcc2d285048f2affc7dada3/src/groups/bmq/bmqt/bmqt_subscription.cpp#L46

This static local variable initialization is not thread safe in general. The probability to observe a bug is small though.

Here are some details and advices:

https://bloomberg.github.io/bde-resources/doxygen/bde_api_prod/group__bslmt__once.html#_details

Expected Behavior

Here is how we did a safe initialization for another component:

https://github.com/bloomberg/blazingmq/blob/08a6d16b1b73d1d71113f80f7c22fcdd3e5392d8/src/groups/bmq/bmqt/bmqt_correlationid.cpp#L33-L42

Will be good to do the same for the problematic line of code above.

Steps To Reproduce

Try to build multiple SubscriptionHandles at the same time from different threads just after the app starts.

BlazingMQ Version

0.90.18

Anything else?

No response

[syuzvinsky]

I am taking this

[678098]

Fixed