[SDK] Added reserve for spans array in BatchSpanProcessor.

[msiddhu]

Changes

Added .reserve for spans_arr in BatchSpanProcessor (Small Optimization)

Helps to allocate the amount of memory needed for number of records so that dynamic memory allocation doesn't happen in the consume method.

.push_back() reallocates memory each time the method is called.

Using .reserve() would avoid memory reallocation as already the memory is allocated.

References:
C++ Vector push_back
C++ Vector reserve

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: msiddhu / name: Siddhartha Malladi (2d120cc, f91df52, dbcc4a7, b6ec481, 9f36f8a)
• ✅ login: marcalff / name: Marc Alff (17aeaba)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.67%. Comparing base (497eaf4) to head (17aeaba).
Report is 91 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2724      +/-   ##
==========================================
+ Coverage   87.12%   87.67%   +0.56%     
==========================================
  Files         200      190      -10     
  Lines        6109     5855     -254     
==========================================
- Hits         5322     5133     -189     
+ Misses        787      722      -65     

Files	Coverage Δ
sdk/src/logs/batch_log_record_processor.cc	89.29% <100.00%> (+1.79%)	⬆️
sdk/src/trace/batch_span_processor.cc	94.12% <100.00%> (+1.70%)	⬆️

... and 105 files with indirect coverage changes

[marcalff]

Looks good to me, thanks for the fix.

See the suggested change to fix the CI failure on code format.

[msiddhu]

Thanks for suggesting. I think CI Checks should starting running now.

[lalitb]

Thanks,

[lalitb]

Similar change can be done for BatchLogProcessor. @msiddhu just in case you can handle as separate as same PR :)

[msiddhu]

Thanks for pointing out. Made the suggested changes. Please review.

[marcalff]

LGTM, thanks for the fix.