Add spec for AlwaysRecord sampler

[majanjua-amzn]

Fixes #4698

Changes

Adds the spec for a new AlwaysRecord sampler being proposed in #4698

Notes

Solutions to this problem in multiple supported languages can already be found below:

• Java
• Python
• JavaScript
• .NET

Checklist

• Related issues #
• Related OTEP(s) #
• Links to the prototypes (when adding or changing features)
• CHANGELOG.md file updated for non-trivial changes
• Spec compliance matrix updated if necessary

[jmacd]

Looks good to me. As we discussed in Sampling SIG, it will help readers to be reminded somewhere in this text that Exporters are already expected to drop these spans, all we're doing is making it easy to setup non-sampling recorded spans by default.

[majanjua-amzn]

Apologies for the delay, pushed a new revision. Please help to run the workflows again, thanks!

[majanjua-amzn]

Perhaps @jmacd could you help to merge? Thanks

[carlosalberto]

Ping @majanjua-amzn (we need a last few details to iron out, but very close to merge this).

[majanjua-amzn]

@carlosalberto, could you help to run the workflows again and approve if all looks good now? Thanks

[majanjua-amzn]

Question in general: Should these be added to the core or contrib repo? For example:

• Where I would add it to core: sdk/trace/samplers or sdk/trace/internal
• Where I would add it to contrib: link

[majanjua-amzn]

@cijothomas finished another revision, please take a look when you can

Also, if anyone has input on the previous comment regarding where to add this feature, please advise:

Question in general: Should these be added to the core or contrib repo? For example:

• Where I would add it to core: sdk/trace/samplers or sdk/trace/internal
• Where I would add it to contrib: link

[cijothomas]

LGTM.
I suggest to request re-reviews from previous approvers, given that the wordings have changed a lot since initial version.

[majanjua-amzn]

Great, made a final revision with respect to the last comment.

If reviewers could re-approve if all looks good and merge this PR, I can also start finalizing my PRs to each other repo and start contributing the feature to OTel core!

Thanks in advance

[majanjua-amzn]

Perhaps @jmacd and @carlosalberto can help provide reviews again, as you folks were early reviewers the first time?

PRs are awaiting the merge of this one in Java, Python, JS, and .NET:

Java: open-telemetry/opentelemetry-java#7877
Python: open-telemetry/opentelemetry-python#4823
JS: open-telemetry/opentelemetry-js#6168
.NET: open-telemetry/opentelemetry-dotnet#6732