Added B3MultiPropagater

[kishannsangani]

Partially fixes #500.

[codecov]

Codecov Report

Merging #680 (cf72950) into main (17264f7) will increase coverage by 0.22%.
The diff coverage is 100.00%.

❗ Current head cf72950 differs from pull request most recent head ef36219. Consider uploading reports for the commit ef36219 to get more accurate results

@@             Coverage Diff              @@
##               main     #680      +/-   ##
============================================
+ Coverage     84.77%   85.00%   +0.22%     
- Complexity     1213     1233      +20     
============================================
  Files           136      137       +1     
  Lines          2936     2980      +44     
============================================
+ Hits           2489     2533      +44     
  Misses          447      447              

Flag	Coverage Δ
7.4	85.00% <100.00%> (+0.22%)	⬆️
8.0	85.05% <100.00%> (+0.22%)	⬆️
8.1	85.05% <100.00%> (+0.22%)	⬆️

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Impacted Files	Coverage Δ
src/API/Trace/Propagation/B3MultiPropagator.php	100.00% <100.00%> (ø)

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