docs(async_utils): add docstrings

[muneeb-i-khan]

Fixes #3384

[codecov-commenter]

Codecov Report

Merging #3398 (b1fee8b) into main (2847879) will increase coverage by 5.19%.
Report is 1 commits behind head on main.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #3398      +/-   ##
==========================================
+ Coverage   75.83%   81.03%   +5.19%     
==========================================
  Files         750      750              
  Lines       11534    11534              
  Branches     1560     1560              
==========================================
+ Hits         8747     9346     +599     
+ Misses       2435     1759     -676     
- Partials      352      429      +77     

Flag	Coverage Δ
longtests	75.81% <100.00%> (-0.02%)	⬇️
win-longtests	79.02% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
cve_bin_tool/async_utils.py	94.48% <100.00%> (+11.72%)	⬆️

... and 22 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[muneeb-i-khan]

I will close this for now and make a new PR