fix: improved performance (only node@12 and above)

[alexander-akait]

This PR contains a:

• bugfix
• new feature
• code refactor
• test update
• typo fix
• metadata update

Motivation / Use-Case

Use worker_thread module when it is possible (faster)

Breaking Changes

No

Additional Info

Only on Node.js 12 and above

[codecov]

Codecov Report

Merging #344 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #344   +/-   ##
=======================================
  Coverage   98.20%   98.20%           
=======================================
  Files           3        3           
  Lines         278      278           
  Branches      118      118           
=======================================
  Hits          273      273           
  Misses          5        5           

Impacted Files	Coverage Δ
src/index.js	97.39% <100.00%> (ø)

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