* add benchmarking
* update README to include benchmarking of individual functions
* README: formatting
* README: add link to Criterion's getting_started
* shell.nix: add gnuplot
Since Criterion.rs uses gnuplot to generate nice plots, add it to the
shell.
* Cargo.toml: fixed microfetch binary name
* benchmark.rs: fix benchmark function's name
* Update README.md
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Co-authored-by: raf <raf@notashelf.dev>