feat(prof): add I/O profiling for macOS

[realFlowControl]

Description

This PR:

• adds I/O profiling to macOS
• cleans up some datatypes in I/O profiling's mod.rs

Why support macOS I/O profiling?

AFAIK we might have a few customers running the profiler on macOS, but the real value is local testability for I/O profiling in our developer environment which is native macOS.

Reviewer checklist

• Test coverage seems ok.
• Appropriate labels assigned.

[datadog-datadog-prod-us1]

⚠️ Tests

✨ Fix all issues with BitsAI or with Cursor

⚠️ Warnings

🧪 1028 Tests failed

testSearchPhpBinaries from integration.DDTrace\Tests\Integration\PHPInstallerTest (Datadog) (Fix with Cursor)

Risky Test
phpvfscomposer://tests/vendor/phpunit/phpunit/phpunit:60

testSimplePushAndProcess from laravel-58-test.DDTrace\Tests\Integrations\Laravel\V5_8\QueueTest (Datadog) (Fix with Cursor)

Risky Test
phpvfscomposer://tests/vendor/phpunit/phpunit/phpunit:97

testSimplePushAndProcess from laravel-8x-test.DDTrace\Tests\Integrations\Laravel\V8_x\QueueTest (Datadog) (Fix with Cursor)

DDTrace\Tests\Integrations\Laravel\V8_x\QueueTest::testSimplePushAndProcess
Test code or tested code printed unexpected output: spanLinksTraceId: 69aadc2d0000000036775f73c4fed0c0
tid: 69aadc2d00000000
hexProcessTraceId: 36775f73c4fed0c0
hexProcessSpanId: 8d746df1561e971b
processTraceId: 3924710551107588288
processSpanId: 10192892739945666331

View all

ℹ️ Info

❄️ No new flaky tests detected

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 3252a71 | Docs | Datadog PR Page | Was this helpful? React with 👍/👎 or give us feedback!}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 62.08%. Comparing base (eebb4fe) to head (3252a71).
⚠️ Report is 5 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3648      +/-   ##
==========================================
- Coverage   62.19%   62.08%   -0.11%     
==========================================
  Files         141      141              
  Lines       13352    13352              
  Branches     1746     1746              
==========================================
- Hits         8304     8290      -14     
- Misses       4256     4269      +13     
- Partials      792      793       +1     

see 3 files with indirect coverage changes

---

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[pr-commenter]

Benchmarks [ profiler ]

Benchmark execution time: 2026-03-06 13:54:48

Comparing candidate commit 3252a71 in PR branch florian/macos-io-profiling with baseline commit eebb4fe in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 30 metrics, 6 unstable metrics.

[morrisonlevi]

I have some more reading to do to review the rest of it, but here's some review.

[pr-commenter]

Benchmarks [ tracer ]

Benchmark execution time: 2026-03-06 14:54:43

Comparing candidate commit 3252a71 in PR branch florian/macos-io-profiling with baseline commit eebb4fe in branch master.

Found 3 performance improvements and 1 performance regressions! Performance is the same for 190 metrics, 0 unstable metrics.

scenario:ComposerTelemetryBench/benchTelemetryParsing

• 🟩 execution_time [-1.880µs; -0.920µs] or [-15.799%; -7.730%]

scenario:EmptyFileBench/benchEmptyFileBaseline

• 🟥 execution_time [+159.554µs; +386.226µs] or [+4.922%; +11.915%]

scenario:MessagePackSerializationBench/benchMessagePackSerialization

• 🟩 execution_time [-6.472µs; -5.928µs] or [-5.950%; -5.450%]

scenario:TraceSerializationBench/benchSerializeTrace-opcache

• 🟩 execution_time [-15.261µs; -7.139µs] or [-4.372%; -2.045%]