[PLAT-12224] Add setTraceCorrelation method to event

[gingerbenw]

Goal

Facilitate trace correlation with the performance client

Design

Add new method to events to enable adding span and trace id's, which can be leveraged by bugsnag-js-performance to correlate traces and errors, but can also be called manually if required

Changeset

Add a new setTraceCorrelation method to events

Testing

Add unit test that calls setTraceCorrelation and verifies the span and trace id are present in the serialised event

[github-actions]

@bugsnag/browser bundle size diff

	Minified	Minfied + Gzipped
Before	43.80 kB	13.43 kB
After	44.22 kB	13.52 kB
±	⚠️ +420 bytes	⚠️ +88 bytes

code coverage diff

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Generated by 🚫 dangerJS against 91611eb

[imjoehaines]

There's a couple of scenarios missing tests:

• if spanId is undefined or null it's still added
• if traceId is undefined or null it's not added

[gingerbenw]

Should we also update the api for setTraceCorrelation to accept undefined | null for the spanId?

public setTraceCorrelation(traceId: string, spanId?: string | null): void

[gingerbenw]

could they both be expected to be null? 🤔

[imjoehaines]

could they both be expected to be null? 🤔

Presumably we shouldn't call setTraceCorrelation if there's no trace ID so I think only span ID should be optional in the API

I don't think it makes sense for span ID to be null as an expected value (i.e. in the TS type definition) but it's javascript so it can easily end up that way at runtime

so I think the signature should be:

setTraceCorrelation(traceId: string, spanId?: string): void

but in the method we can't assume they have the right types