Improve rust coverages

[try-agaaain]

test both rust and cpp, issue #13

[codecov]

Codecov Report

Merging #67 (98b94c2) into main (a55b78b) will increase coverage by 7.98%.
The diff coverage is 100.00%.

❗ Current head 98b94c2 differs from pull request most recent head 5de3cdf. Consider uploading reports for the commit 5de3cdf to get more accurate results

@@            Coverage Diff             @@
##             main      #67      +/-   ##
==========================================
+ Coverage   64.74%   72.72%   +7.98%     
==========================================
  Files          10       10              
  Lines         919      924       +5     
==========================================
+ Hits          595      672      +77     
+ Misses        324      252      -72     

Impacted Files	Coverage Δ
runtime/wasm-bpf-rs/src/lib.rs	77.14% <100.00%> (+2.14%)	⬆️

... and 4 files with indirect coverage changes

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