fix build warnings

[Monster880]

fix build warnings

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Monster880
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[sre-ci-robot]

Welcome @Monster880! It looks like this is your first PR to milvus-io/milvus-sdk-cpp 🎉

[Monster880]

/assign @matrixji

[matrixji]

Hi, @Monster880 Thanks for your contributions, the clang-format-check failed, you should follow the code-style-for-milvus-c-sdk guide to do clang-format locally before raising PR.