Improve performance of parsing headers

[bdraco]

After we have a complete header we always have to convert it to a new bytes object. For almost every case we get the header in a single read. In this case its much faster to convert to bytes once. If the header gets split across multiple reads it will be a bit slower but this is the uncommon case.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.76%. Comparing base (0d6a83e) to head (ebafbb4).
Report is 2 commits behind head on master.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #10073   +/-   ##
=======================================
  Coverage   98.76%   98.76%           
=======================================
  Files         121      121           
  Lines       36860    36860           
  Branches     4396     4396           
=======================================
  Hits        36403    36403           
  Misses        311      311           
  Partials      146      146           

Flag	Coverage Δ
CI-GHA	98.64% <ø> (ø)
OS-Linux	98.33% <ø> (ø)
OS-Windows	96.18% <ø> (ø)
OS-macOS	97.43% <ø> (ø)
Py-3.10.11	97.29% <ø> (+<0.01%)	⬆️
Py-3.10.15	97.88% <ø> (+0.05%)	⬆️
Py-3.11.10	97.88% <ø> (+<0.01%)	⬆️
Py-3.11.9	97.34% <ø> (+0.01%)	⬆️
Py-3.12.7	98.39% <ø> (ø)
Py-3.13.0	98.39% <ø> (+<0.01%)	⬆️
Py-3.9.13	97.21% <ø> (ø)
Py-3.9.20	97.74% <ø> (-0.05%)	⬇️
Py-pypy7.3.16	97.36% <ø> (ø)
VM-macos	97.43% <ø> (ø)
VM-ubuntu	98.33% <ø> (ø)
VM-windows	96.18% <ø> (ø)

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[codspeed-hq]

CodSpeed Performance Report

Merging #10073 will not alter performance

_{Comparing find_header_perf (ebafbb4) with master (0d6a83e)}

Summary

✅ 44 untouched benchmarks

[patchback]

Backport to 3.11: 💚 backport PR created

✅ Backport PR branch: patchback/backports/3.11/349b756592bd9baee4ef89e2ed9a770b2800cce5/pr-10073

Backported as #10083

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[patchback]

Backport to 3.12: 💚 backport PR created

✅ Backport PR branch: patchback/backports/3.12/349b756592bd9baee4ef89e2ed9a770b2800cce5/pr-10073

Backported as #10084

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.