fix(rust): fix async feature compile error

[attila-lin]

fix this compile error with following feature gate

polars = { version = "0.43", features = [
     "lazy",
     "async",
     "parquet",
     "is_in",
     "dtype-categorical",
     "performant",
] }

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.96%. Comparing base (79b91c3) to head (196f4cb).
Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18682      +/-   ##
==========================================
+ Coverage   79.92%   79.96%   +0.04%     
==========================================
  Files        1513     1513              
  Lines      203334   203334              
  Branches     2892     2892              
==========================================
+ Hits       162510   162598      +88     
+ Misses      40276    40188      -88     
  Partials      548      548              

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