Metric callback improve

[TingDaoK]

Move the telemetry callback to be invoked from the meta request event loop

• Previously, we invoke the telemetry callback once the send_data gets clean up, which happens when the s3 request gone, or the send_data get cleaned up.
• Now, we schedule the callback to be invoked from the events on the meta request
  • When the send_data get set up, which will happen if the request prepared the http message (before the signing).
  • When the finished_request invoked, which is the request will not be retried anymore and finished.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (2c19abf) 88.74% compared to head (44382a1) 88.74%.

Additional details and impacted files

[](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs) ```diff @@ Coverage Diff @@ ## main #390 +/- ## ======================================= Coverage 88.74% 88.74% ======================================= Files 21 21 Lines 5986 6024 +38 ======================================= + Hits 5312 5346 +34 - Misses 674 678 +4 ``` | [Files](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs) | Coverage Δ | | |---|---|---| | [source/s3\_auto\_ranged\_get.c](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs#diff-c291cmNlL3MzX2F1dG9fcmFuZ2VkX2dldC5j) | `98.28% <100.00%> (+0.02%)` | :arrow_up: | | [source/s3\_copy\_object.c](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs#diff-c291cmNlL3MzX2NvcHlfb2JqZWN0LmM=) | `83.33% <100.00%> (+0.27%)` | :arrow_up: | | [source/s3\_default\_meta\_request.c](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs#diff-c291cmNlL3MzX2RlZmF1bHRfbWV0YV9yZXF1ZXN0LmM=) | `95.70% <100.00%> (-0.53%)` | :arrow_down: | | [source/s3\_request.c](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs#diff-c291cmNlL3MzX3JlcXVlc3QuYw==) | `95.20% <100.00%> (+0.07%)` | :arrow_up: | | [source/s3\_util.c](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs#diff-c291cmNlL3MzX3V0aWwuYw==) | `99.62% <100.00%> (+0.01%)` | :arrow_up: | | [source/s3\_auto\_ranged\_put.c](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs#diff-c291cmNlL3MzX2F1dG9fcmFuZ2VkX3B1dC5j) | `92.58% <98.64%> (-0.11%)` | :arrow_down: | | [source/s3\_meta\_request.c](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs#diff-c291cmNlL3MzX21ldGFfcmVxdWVzdC5j) | `90.62% <83.33%> (-0.15%)` | :arrow_down: |