* Add the InstrumentKind type and vars to sdk/metric
* Add the Instrument type to sdk/metric
* Add the Stream type to sdk/metric
* Add the View type to sdk/metric
* Add NewView to create Views matching OTel spec
* Add unit tests for NewView
* Add changes to changelog
* Apply suggestions from code review
Co-authored-by: Anthony Mirabella <a9@aneurysm9.com>
* Update CHANGELOG.md
* Update match and mask comments of Instrument
* Explain wildcard logic in NewView with comment
* Drop views that replace name for multi-inst match
* Comment how users are expected to match zero-vals
* Remove InstrumentKind and Scope from Stream
* Fix redundant word in NewView comment
Co-authored-by: Anthony Mirabella <a9@aneurysm9.com>
Co-authored-by: Chester Cheung <cheung.zhy.csu@gmail.com>
