lf.LanguageModel to expose flags retry_interval and exponential_backoff.

[copybara-service]

lf.LanguageModel to expose flags retry_interval and exponential_backoff.

[codecov-commenter]

Codecov Report

Merging #59 (4d50b81) into main (17978d0) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 4d50b81 differs from pull request most recent head be5139f. Consider uploading reports for the commit be5139f to get more accurate results

@@           Coverage Diff           @@
##             main      #59   +/-   ##
=======================================
  Coverage   97.06%   97.06%           
=======================================
  Files          42       42           
  Lines        3479     3481    +2     
  Branches      738      738           
=======================================
+ Hits         3377     3379    +2     
  Misses         46       46           
  Partials       56       56           

Files	Coverage Δ
langfun/core/language_model.py	100.00% <100.00%> (ø)
langfun/core/llms/llama_cpp.py	100.00% <ø> (ø)
langfun/core/llms/openai.py	94.89% <ø> (ø)