fix: Better document default integrations

[Swatinem]

This also exposes a new global with_integration function which is also
used in existing integrations.

[jan-auer]

Why would you deduplicate integrations - is this unified behavior? Spontaneously, I'd argue that it might make perfect sense to initialize an integration twice with different settings.

Of course, with_integration would then only return one of them, but potentially there is no need to access such integrations later on.

[Swatinem]

Of course, with_integration would then only return one of them, but potentially there is no need to access such integrations later on.

One of the obvious usecases is to customize the default PanicIntegration with a custom extractor. Since that relies on the with_integration ordering, it would never use the custom extractor, unless you explicitly use default_integrations: false, and manually add all the defaults.

On the other hand, it totally makes sense to have multiple instances of event-processor-like integrations.

I think I will revert the unique-ness check, and rather better document this case, and also the default integrations.

[jan-auer]

unless you explicitly use default_integrations: false, and manually add all the defaults

But isn't that exactly what the unified spec says? My understanding was that you need to disable default integrations if you want to customize one of them.

[Swatinem]

But isn't that exactly what the unified spec says?

Hm, it doesn’t really say anything about integrations :-D

Anyhow, I added some more docs here.