fix(async search): recover frac search

[forshev]

Description

Handle panics during frac search in async searches
Add async search panics metric

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[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
Bitmask-4	174405	ef3059
	0.00 B/op	3.00 B/op	NaN	🔴
FindSequence_Random/medium-4	174405	ef3059
	11839.40 MB/s	10315.58 MB/s	0.87	🔴
	86.49 ns/op	99.27 ns/op	1.15	🔴
FindSequence_Random/small-4	174405	ef3059
	10280.15 MB/s	4344.58 MB/s	0.42	🔴
	24.90 ns/op	58.92 ns/op	2.37	🔴
GenerateDocs-4	174405	ef3059
	952.20 ns/op	1142.00 ns/op	1.20	🔴
ProcessDocuments-4	174405	ef3059
	381.00 B/op	33319.00 B/op	87.45	🔴
	4.00 allocs/op	5.00 allocs/op	1.25	🔴

[codecov-commenter]

Codecov Report

❌ Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 71.61%. Comparing base (f8f35dd) to head (d6ce825).

Files with missing lines	Patch %	Lines
asyncsearcher/async_searcher.go	50.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #342      +/-   ##
==========================================
- Coverage   71.61%   71.61%   -0.01%     
==========================================
  Files         204      204              
  Lines       14820    14823       +3     
==========================================
+ Hits        10614    10616       +2     
+ Misses       3448     3447       -1     
- Partials      758      760       +2     

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[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
FindSequence_Random/medium-4	174405	898402
	11839.40 MB/s	10328.72 MB/s	0.87	🔴
	86.49 ns/op	99.14 ns/op	1.15	🔴
FindSequence_Random/small-4	174405	898402
	10280.15 MB/s	5417.91 MB/s	0.53	🔴
	24.90 ns/op	47.25 ns/op	1.90	🔴
ProcessDocuments-4	174405	898402
	381.00 B/op	33192.00 B/op	87.12	🔴
	4.00 allocs/op	5.00 allocs/op	1.25	🔴

[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
FindSequence_Random/large-4	f8f35d	26d3be
	13368.39 MB/s	12005.29 MB/s	0.90	🔴
	1226.00 ns/op	1365.00 ns/op	1.11	🔴
GenerateDocs-4	f8f35d	26d3be
	947.70 ns/op	1139.00 ns/op	1.20	🔴