fix: Make etw logs exporter synchronous

[berkus]

Remove block_on calls and remove otel Exporter trait impl.

Fixes #511

Changes

ETW Logs exporter now does not invoke asynchronous Exporter impl under the hood. The call was a fake (using block_on) anyway, and it could cause problems if, for example, a tracing log macro was called under another block_on() async block - nesting block_on()s is forbidden.

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

❌ Patch coverage is 82.14286% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 55.7%. Comparing base (4b24b0c) to head (4670659).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
opentelemetry-etw-logs/src/exporter/mod.rs	79.1%	5 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #514     +/-   ##
=======================================
- Coverage   55.8%   55.7%   -0.1%     
=======================================
  Files         77      77             
  Lines      12500   12472     -28     
=======================================
- Hits        6980    6954     -26     
+ Misses      5520    5518      -2     

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[cijothomas]

@psandana Could you take a look as well before merge?

[psandana]

LGTM. I would include a test that uses block_on() to prevent regressions.

[cijothomas]

LGTM. I would include a test that uses block_on() to prevent regressions.

@berkus merging now. Would you send a follow up to add a test @psandana recommended? I think its an important test to prove that this indeed fixes the issue.

[berkus]

Yep, will add a test promptly.