Add internal _time feature to the Rust CLI

[ia0]

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[gemini-code-assist]

Code Review

This pull request introduces an internal _time feature to measure inference time in the Rust CLI. The implementation is mostly correct, but I've found a critical issue in how the average inference time is calculated, which leads to an incorrect metric. I've also identified a potential division-by-zero error and a minor style issue. My review includes suggestions to fix these issues to ensure the feature provides accurate measurements and the code is robust and idiomatic.