[Bug]: Examples disregard `FD_COUNT` and `FD_NAMES` env variables

[rvolosatovs]

Is there an existing issue for this?

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Code of Conduct

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Current Behaviour

FD_COUNT and FD_NAMES env variables are provided to e.g. Rust examples, but they completely disregard them and instead use hard-coded values. Often without even checking FD_COUNT.

Expected Behaviour

Since we want to show the best practices in examples in this repo, the env variables should be respected.

Environment Information

irrelevant

Steps To Reproduce

No response