chore: sample trace before flush unless already sampled

[ZStriker19]

What does this PR do?
This PR causes a trace to be sampled during flush with the intent of making sampling lazy.
Motivation:
Lazy sampling allows sampling on tags and resource

Additional Notes:

How to test the change?

Unsure? Have a question? Request a review!

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.84%. Comparing base (4fff83a) to head (7203b51).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3946      +/-   ##
==========================================
- Coverage   97.85%   97.84%   -0.01%     
==========================================
  Files        1303     1303              
  Lines       78139    78142       +3     
  Branches     3894     3895       +1     
==========================================
- Hits        76462    76461       -1     
- Misses       1677     1681       +4     

Flag	Coverage Δ
	97.84% <100.00%> (-0.01%)	⬇️

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[pr-commenter]

Benchmarks

Benchmark execution time: 2024-09-25 20:58:19

Comparing candidate commit 529895a in PR branch zachg/sample_before_trace_flush with baseline commit 4fff83a in branch master.

Found 3 performance improvements and 0 performance regressions! Performance is the same for 21 metrics, 1 unstable metrics.

scenario:tracing - 1 span trace - no network

• 🟩 throughput [+1075.173op/s; +1418.034op/s] or [+9.211%; +12.149%]

scenario:tracing - 10 span trace - no network

• 🟩 throughput [+294.722op/s; +435.034op/s] or [+11.654%; +17.202%]

scenario:tracing - 100 span trace - no network

• 🟩 throughput [+57.473op/s; +82.268op/s] or [+20.344%; +29.120%]