feat: add read_frame and loop_indices to public api

[tlambert03]

making read_frame and loop_indices public

[codecov]

Codecov Report

Merging #181 (67b1aa6) into main (788590b) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #181      +/-   ##
==========================================
+ Coverage   95.32%   95.33%   +0.01%     
==========================================
  Files          17       17              
  Lines        2331     2338       +7     
==========================================
+ Hits         2222     2229       +7     
  Misses        109      109              

Files	Coverage Δ
src/nd2/_util.py	98.66% <100.00%> (+0.07%)	⬆️
src/nd2/nd2file.py	97.38% <100.00%> (+0.02%)	⬆️
src/nd2/readers/_modern/modern_reader.py	93.28% <100.00%> (ø)

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[codspeed-hq]

CodSpeed Performance Report

Merging #181 will not alter performance

_{Comparing pub-api (67b1aa6) with main (788590b)}

Summary

✅ 13 untouched benchmarks