perf: do not tie field lifetime to buffer lifetime

[dkharms]

Description

In tokenLIDsWorker we allocate continuous buffer for storing non-existing (yet) tokens (field:value pairs) and later we use some chunks of this buffer as keys in FieldTIDs hashmap -- so we prolongate lifetime of the whole buffer.

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.20%. Comparing base (560903e) to head (b60ba98).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #507      +/-   ##
==========================================
- Coverage   71.37%   71.20%   -0.17%     
==========================================
  Files         250      250              
  Lines       21709    21711       +2     
==========================================
- Hits        15494    15459      -35     
- Misses       5063     5088      +25     
- Partials     1152     1164      +12     

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[github-actions]

🔴 Performance Degradation

Some benchmarks have degraded compared to the previous run.
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Name	Previous	Current	Ratio	Verdict
ProcessDocuments-4	e37ed3	9272e5
	567.00 B/op	13086.00 B/op	23.08	🔴

[github-actions]

🔴 Performance Degradation

Some benchmarks have degraded compared to the previous run.
Click on Show table button to see full list of degraded benchmarks.

Show table

Name	Previous	Current	Ratio	Verdict
MutexListAppend-4	560903	6fa32d
	188.06 MB/s	167.06 MB/s	0.89	🔴