fix: Stop using Azure's EventHubs batch spanContext map for storing DD span contexts

[jcstorms1]

What does this PR do?

• Stores our span contexts in a weakMap

Motivation

Originally we used Azure's built in spanContext map to store span context for our span links. This could cause conflicts with Azure Application Inights if OTel is enabled, because Azure uses this map to generate their span links.

Plugin Checklist

• Unit tests.
• Integration tests.
• Benchmarks.
• TypeScript definitions.
• TypeScript tests.
• API documentation.
• CI jobs/workflows.

Additional Notes

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.83%. Comparing base (19a7bfc) to head (f11e330).
⚠️ Report is 98 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6943      +/-   ##
==========================================
+ Coverage   84.60%   84.83%   +0.23%     
==========================================
  Files         505      515      +10     
  Lines       21165    22022     +857     
==========================================
+ Hits        17907    18683     +776     
- Misses       3258     3339      +81     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[github-actions]

Overall package size

Self size: 3.58 MB
Deduped: 4.46 MB
No deduping: 4.46 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | import-in-the-middle | 1.15.0 | 127.66 kB | 856.24 kB | | dc-polyfill | 0.1.10 | 26.73 kB | 26.73 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

[BridgeAR]

The tests are sadly still failing

[BridgeAR]

Suggested change

// TODO: Fix this test / esm issue

[jcstorms1]

The test is skipped again. As long as we pass the azure-functions tests we know my change is working.

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-12-12 16:00:27

Comparing candidate commit f11e330 in PR branch storms/refactor-event-hubs-batch-contexts with baseline commit 19a7bfc in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 290 metrics, 30 unstable metrics.

[BridgeAR]

Could you please add a regression test that checks that ctx.batch._spanContexts is not changed anymore?