fix #6446

[LittleLittleCloud]

We are excited to review your PR.

So we can do the best job, please check:

• There's a descriptive title that will make sense to other developers some time from now.
• There's associated issues. All PR's should have issue(s) associated - unless a trivial self-evident change such as fixing a typo. You can use the format Fixes #nnnn in your description to cause GitHub to automatically close the issue(s) when your PR is merged.
• Your change description explains what the change does, why you chose your approach, and anything else that reviewers should know.
• You have included any necessary tests in the same PR.

fix #6446

[codecov]

Codecov Report

Merging #6447 (2dff87b) into main (87337c0) will decrease coverage by 0.08%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6447      +/-   ##
==========================================
- Coverage   68.55%   68.46%   -0.09%     
==========================================
  Files        1170     1173       +3     
  Lines      246977   247651     +674     
  Branches    25792    25846      +54     
==========================================
+ Hits       169303   169548     +245     
- Misses      70951    71374     +423     
- Partials     6723     6729       +6     

Flag	Coverage Δ
Debug	68.46% <100.00%> (-0.09%)	⬇️
production	62.85% <ø> (-0.11%)	⬇️
test	88.92% <100.00%> (-0.05%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...Microsoft.ML.AutoML.Tests/AutoMLExperimentTests.cs	96.52% <100.00%> (ø)
...icrosoft.ML.FastTree/RandomForestClassification.cs	51.51% <0.00%> (-33.58%)	⬇️
...rc/Microsoft.ML.FastTree/RandomForestRegression.cs	54.14% <0.00%> (-17.29%)	⬇️
.../Standard/LogisticRegression/LbfgsPredictorBase.cs	61.34% <0.00%> (-11.14%)	⬇️
...Microsoft.ML.Mkl.Components/OlsLinearRegression.cs	56.33% <0.00%> (-10.52%)	⬇️
src/Microsoft.ML.FastTree/Training/StepSearch.cs	57.42% <0.00%> (-4.96%)	⬇️
...ree/TreeEnsemble/InternalQuantileRegressionTree.cs	61.84% <0.00%> (-3.44%)	⬇️
...ML.FastTree/TreeEnsemble/InternalRegressionTree.cs	72.68% <0.00%> (-1.43%)	⬇️
src/Microsoft.ML.Maml/MAML.cs	25.38% <0.00%> (-0.51%)	⬇️
src/Microsoft.ML.LightGbm/LightGbmTrainerBase.cs	79.50% <0.00%> (-0.28%)	⬇️
... and 11 more