add x-datadog-origin to TraceContext

[jo-me]

What does this PR do?

This PR adds the x-datadog-origin header to the TraceContext so that traces can be linked to synthetic tests

Motivation

Traces were not linked to synthetic tests

Testing Guidelines

In local fork

Additional Notes

partly fixes #189

Types of changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Checklist

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog

The program was tested solely for our own use cases, which might differ from yours.

Jochen Mehlhorn [email protected], Mercedes-Benz Tech Innovation GmbH

Provider Information

[purple4reina]

I'm not sure this PR does what you think it does. Have you been able to test with a sample app to confirm? I'm happy to help you set up a sample app for testing.

[jo-me]

Hmm, it is just including an additional header value in the tracecontext, isnt it?

Have you seen #189 that a colleague of mine created for this? That is what we're trying to solve.
It is strange that the direct links from DD synthetic tests to the related traces is not working if this datadog-lambda-go lib is involved. For non-lambda workloads it works out of the box. If you have other tips related to this issue we'd be happy to discuss in #189