fix: Lazy csv + projection; respect null values arg

[ritchie46]

fixes #15515

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.95%. Comparing base (3600b16) to head (11c8813).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #16077      +/-   ##
==========================================
- Coverage   80.98%   80.95%   -0.03%     
==========================================
  Files        1386     1386              
  Lines      178452   178439      -13     
  Branches     3075     3075              
==========================================
- Hits       144512   144459      -53     
- Misses      33448    33488      +40     
  Partials      492      492              

Flag	Coverage Δ
python	74.50% <100.00%> (-0.04%)	⬇️
rust	78.12% <100.00%> (-0.03%)	⬇️

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