fix(minor): Fix incorrect syscalls

[hassila]

Description

Deducts the syscall overhead for cleaner statistics.
Fix the broken API for setup closures.

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Minimal checklist:

• I have performed a self-review of my own code
• I have added DocC code-level documentation for any public interfaces exported by the package
• I have added unit and/or integration tests that prove my fix is effective or that my feature works

[github-actions]

Pull request benchmark comparison [ubuntu-latest] with 'main' run at 2023-09-14T09:49:58+00:00
Pull request had performance regressions

[codecov]

Codecov Report

Merging #187 (73f24f4) into main (1e3568b) will decrease coverage by 0.15%.
The diff coverage is 51.35%.

❗ Current head 73f24f4 differs from pull request most recent head d7b3cf5. Consider uploading reports for the commit d7b3cf5 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #187      +/-   ##
==========================================
- Coverage   71.14%   70.99%   -0.15%     
==========================================
  Files          29       29              
  Lines        3652     3671      +19     
==========================================
+ Hits         2598     2606       +8     
- Misses       1054     1065      +11     

Files Changed	Coverage Δ
.../Benchmark/Benchmark+ConvenienceInitializers.swift	0.00% <0.00%> (ø)
Sources/Benchmark/Benchmark.swift	73.05% <ø> (ø)
Sources/Benchmark/BenchmarkExecutor.swift	93.77% <100.00%> (+0.16%)	⬆️
Sources/Benchmark/BenchmarkRunner.swift	59.09% <100.00%> (+0.10%)	⬆️

Files Changed	Coverage Δ
.../Benchmark/Benchmark+ConvenienceInitializers.swift	0.00% <0.00%> (ø)
Sources/Benchmark/Benchmark.swift	73.05% <ø> (ø)
Sources/Benchmark/BenchmarkExecutor.swift	93.77% <100.00%> (+0.16%)	⬆️
Sources/Benchmark/BenchmarkRunner.swift	59.09% <100.00%> (+0.10%)	⬆️

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