Cancel/Pause stream optimization

[TingDaoK]

Issue #, if available:

• We previously cancel/pause meta request by not making any new request, but wait for anything inflight to complete, which doesn't need to happen.
• We want to cancel streams quickly without waiting for http level

Description of changes:

• Keep a list of requests that have ongoing http level activities.
• When cancel or pause invoked, go through the list and cancel the underlying http streams, which will actually cancel the request without waiting for HTTP req/resp to complete.
• But, for MPU cancel, we still need to wait for abort MPU to complete.

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

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (bb6af37) 88.69% compared to head (5dc6d7d) 88.72%.

Additional details and impacted files

[](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/395?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs) ```diff @@ Coverage Diff @@ ## main #395 +/- ## ========================================== + Coverage 88.69% 88.72% +0.02% ========================================== Files 21 21 Lines 5962 5986 +24 ========================================== + Hits 5288 5311 +23 - Misses 674 675 +1 ``` | [Files](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/395?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\_put.c](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/395?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs#diff-c291cmNlL3MzX2F1dG9fcmFuZ2VkX3B1dC5j) | `92.69% <100.00%> (+0.01%)` | :arrow_up: | | [source/s3\_meta\_request.c](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/395?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs#diff-c291cmNlL3MzX21ldGFfcmVxdWVzdC5j) | `90.76% <100.00%> (+0.24%)` | :arrow_up: | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/awslabs/aws-c-s3/pull/395/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=awslabs)