Add lock to Pubsub.execute_command to ensure only one connection is created

[dlunch]

Pull Request check-list

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Description of change

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.36%. Comparing base (1032660) to head (3fc64f2).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #19      +/-   ##
==========================================
- Coverage   92.40%   92.36%   -0.04%     
==========================================
  Files         119      119              
  Lines       30727    30743      +16     
==========================================
+ Hits        28392    28395       +3     
- Misses       2335     2348      +13     

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[dlunch]

is it better patch it upstream?

[zach-iee]

is it better patch it upstream?

it would be best to patch the upstream as well as we can remove this PR once upstream release a new release

Also could you please add a test case for this code (ex. lock is already acquired and trying to acquire a connection doesn't return a new connection)?

[zach-iee]

i'll review again, when a test is added

[zach-iee]

@dlunch any update?

[dlunch]

Sorry, i was on vacation. i'll add test this week

[zach-iee]

👍
please create a PR to 4.4 branch in order to backmerge