Fixes#6980
Towards #6887
## What
- Any references to sdk/metric/x in documentation, tests, or examples
are updated to redirect users to use the cardinality limit feature in
the SDK.
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Co-authored-by: Robert Pająk <pellared@hotmail.com>
* Add agg limiting func
* Add unit test for limitAttr
* Add limiting to aggregate types
* Add internal x pkg for experimental feature-flagging
* Connect cardinality limit to metric SDK
* Replace limitAttr fn with limiter type
The Attribute method is still inlinable.
* Use x.CardinalityLimit directly
* Simplify limiter test
* Add limiter benchmark
* Document the AggregationLimit field
* Test sum limits
* Test limit for last value
* Test histogram limit
* Refactor expo hist test to use existing fixtures
The tests for the exponential histogram create their own testing
fixtures. There is nothing these new fixtures do that cannot already be
done with the existing testing fixtures used by all the other aggregate
functions. Unify the exponential histogram testing to use the existing
fixtures.
* Test the ExponentialHistogram limit
* Fix lint
* Add docs
* Rename aggregation field to aggLimit
---------
Co-authored-by: Robert Pająk <pellared@hotmail.com>
* Add the internal experimental metric feature pkg
* Interpret empty envvar same as unset
* Test Exemplars and CardinalityLimit
* Fix empty test for CardinalityLimit
* Abstract common testing patterns
* Add test cases from review feedback
* Rename assertions based on review feedback
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Co-authored-by: Chester Cheung <cheung.zhy.csu@gmail.com>
