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 ✅

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

Additional details and impacted files

@@            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	Coverage Δ
source/s3_auto_ranged_put.c	92.69% <100.00%> (+0.01%)	⬆️
source/s3_meta_request.c	90.76% <100.00%> (+0.24%)	⬆️

... and 1 file with indirect coverage changes