fix: Improve load test external worker timing collection

[juliusgeo]

Description

Parallelize the timing collection so it doesn't choke when we run beefy load tests.

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Documentation change (pure documentation change)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking changes to code which doesn't change any behaviour)
• CI (any automation pipeline changes)
• Chore (changes which are not directly related to any business logic)
• Test changes (add, refactor, improve or change a test)
• This change requires a documentation update

What's Changed

• Add a list of tasks or features here...

Checklist

Changes have been:

• Tested (unit, integration, or manually with steps specified)
• Linted and formatted
• Documented (where applicable)
• Added to CHANGELOG (where applicable) -- see Keep a Changelog

---

🤖 AI Disclosure

• I acknowledge that an LLM was used in the creation of this Pull Request, in accordance with Hatchet's AI_POLICY.md.

• Details: [e.g. generating tests, writing docs]

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Project	Deployment	Actions	Updated (UTC)
hatchet-docs	Ready	Preview, Comment	Jul 28, 2026 8:30pm

[github-actions]

⚠️ Optional test failure: The load-deadlock job failed on this PR (optimistic-scheduling=false). This check is non-mandatory and does not block merging, but may be worth investigating. View logs

[github-actions]

Benchmark results

goos: linux
goarch: amd64
pkg: github.com/hatchet-dev/hatchet/internal/msgqueue
cpu: AMD Ryzen 9 7950X3D 16-Core Processor          
                              │ /tmp/new.txt │
                              │    sec/op    │
CompressPayloads_1x10KiB-8      77.53µ ±  4%
CompressPayloads_10x10KiB-8     867.1µ ±  1%
CompressPayloads_10x100KiB-8    10.45m ±  2%
CompressPayloads_Concurrent-8   58.25µ ± 36%
geomean                         449.8µ

                              │ /tmp/new.txt │
                              │     B/op     │
CompressPayloads_1x10KiB-8      10.93Ki ± 0%
CompressPayloads_10x10KiB-8     108.3Ki ± 2%
CompressPayloads_10x100KiB-8    2.920Mi ± 0%
CompressPayloads_Concurrent-8   54.22Ki ± 0%
geomean                         117.7Ki

                              │ /tmp/new.txt │
                              │  allocs/op   │
CompressPayloads_1x10KiB-8        5.000 ± 0%
CompressPayloads_10x10KiB-8       32.00 ± 0%
CompressPayloads_10x100KiB-8      63.00 ± 2%
CompressPayloads_Concurrent-8     17.00 ± 0%
geomean                           20.35

_{Compared against main (559b502)}