Close EventSource instances

[moralejo]

Avoid a lot of zombie processes when using these functions repeatedly

[codecov]

Codecov Report

Attention: Patch coverage is 93.42105% with 5 lines in your changes missing coverage. Please review.

Project coverage is 73.50%. Comparing base (9bab172) to head (bc7b13e).
Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
lstchain/image/modifier.py	93.42%	5 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1316   +/-   ##
=======================================
  Coverage   73.50%   73.50%           
=======================================
  Files         134      134           
  Lines       14211    14211           
=======================================
  Hits        10446    10446           
  Misses       3765     3765           

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[maxnoe]

better directly use the context manager:

with EventSource(...) as mc_reader:
    ...

[gabemery]

I agree with this change, but also with the comment by maxnoe. So I will wait for its implementation before approving the PR.

[moralejo]

I hope I didn't mess ups with the indents... I wonder if it was really worth. I will check again later, back to Draft