Add file locking mechanism

[NeuralFlux]

linked to biothings/biothings_explorer#896

[codecov]

Codecov Report

Attention: Patch coverage is 21.05263% with 15 lines in your changes missing coverage. Please review.

Project coverage is 51.43%. Comparing base (0e5358b) to head (55c6640).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/misc.ts	21.05%	15 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #8      +/-   ##
==========================================
- Coverage   53.66%   51.43%   -2.23%     
==========================================
  Files           5        5              
  Lines         259      278      +19     
  Branches       38       41       +3     
==========================================
+ Hits          139      143       +4     
- Misses        115      130      +15     
  Partials        5        5              

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