Fix missing headers for fetch

[berndfuhrmann]

Issue #679:

Description of changes:

• For integration tests, added a small HTTP server that receives requests made via fetch. This offers the ability to check headers that were actually supplied in the request.
• I reverted a changed introduced recently, so X-Amzn-Trace-Id headers are sent again
• Exporting enableCapture function. This provides the ability to use this without changing globals. It also provides the ability to use different Request classes, e.g. undici.Request instead of globalThis.Request. This should provide a way for anyone who wants to use undici with dispatcher.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[berndfuhrmann]

Also added this bug to undici:
nodejs/undici#3630

[jj22ee]

Thanks for the fix and improvements for this and the undici package!

The changes lgtm. We can remove package-lock.json in fetch package as this is a monorepo, I suppose your changes to package.json should affect the root package-lock.json instead.

Not sure why the codecov is failing suddenly on the Node16.x/Ubuntu test, I'll look into this (and also #688). It should be unrelated to your PR.

• Randomly got it to work in a different PR somehow, took a couple of tries: https://github.com/aws/aws-xray-sdk-node/actions/runs/10929993247/job/31109948820?pr=686

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.56%. Comparing base (9552603) to head (5470288).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #687   +/-   ##
=======================================
  Coverage   83.56%   83.56%           
=======================================
  Files          36       36           
  Lines        1813     1813           
=======================================
  Hits         1515     1515           
  Misses        298      298           

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[jj22ee]

LGTM 🚢

[jj22ee]

I've fixed the failing codecov in #692 and merged the fix into your branch, along with some minor fixes to the package-lock files.