Restore per-attempt retry logging in OkHttpGrpcSender

[thswlsqls]

Fixes #8966

Related to #8854, #6614

Description

• Retry ConnectException, add retry logging #6614 added FINER logs for each retry attempt. fix: retry OTLP gRPC responses with trailer status #8854 moved gRPC retries from RetryInterceptor into OkHttpGrpcSender.sendAttempt() and dropped them.
• This restores them in the attempt callback, with the level and wording of RetryInterceptor and JdkHttpSender: Attempt N failed with (non-)retryable exception (exception passed as the Throwable) and Attempt N returned (non-)retryable response: ....
• The response suffix shows the gRPC status and message, since the OkHttp Response is no longer at hand.
• The exception predicate now runs once before the retry checks, so it is also called on the last attempt. RetryInterceptor does the same.
• Logs are written only when retry is enabled, as before. The logger is now OkHttpGrpcSender instead of RetryInterceptor (same package).

Testing done

• Added OkHttpGrpcSenderTest#send_retryEnabled_logsEachFailedAttempt: closed port, 2 attempts; expects Attempt 0 ... and Attempt 1 failed with retryable exception.
• With the main-code change reverted, the test fails (no log records).
• ./gradlew :exporters:sender:okhttp:check passed, 57 tests. internal package, no apidiff change.

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Waiting on the author · refreshed 2026-10-19 00:48 UTC

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[codecov]

Codecov Report

❌ Patch coverage is 40.00000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.40%. Comparing base (b32298a) to head (fcbd32e).

Files with missing lines	Patch %	Lines
...orter/sender/okhttp/internal/OkHttpGrpcSender.java	40.00%	4 Missing and 2 partials ⚠️

❌ Your patch check has failed because the patch coverage (40.00%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8967      +/-   ##
============================================
- Coverage     90.40%   90.40%   -0.01%     
  Complexity    10898    10898              
============================================
  Files          1015     1015              
  Lines         29843    29850       +7     
  Branches       3896     3899       +3     
============================================
+ Hits          26981    26986       +5     
- Misses         1910     1911       +1     
- Partials        952      953       +1     

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