Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>

)

* chore: Remove `@BetaApi` annotations for the de-facto GA features

Those features have been under `BetaApi` annotation for 2-3+ years.
They are:
- Long running operations logic
- Streaming logic
- Fields extractor logic
- Interceptors logic
- Response metadata logic

Many of the classes under gax-httpjson module remain `BetaApi` as those are much younger than grpc and shared classes, and will be cleaned up with httpjson module GA (which whill hopefully happen in H1).

This also addresses a couple old issues: #1095 and #702

* undeprecate Distribution and Pages

* chore: check downstream libraries in gax

* chore: fix typo

* chore: run check on all libraries

* chore: check all libaries

* chore: fix tab space

* chore: only run if checks if labelled

* chore: fix comments

* Update .kokoro/downstream-client-library-check.sh

Co-authored-by: Chanseok Oh <chanseok@google.com>

* Update .kokoro/downstream-client-library-check.sh

Co-authored-by: Chanseok Oh <chanseok@google.com>

* Update .kokoro/downstream-client-library-check.sh

Co-authored-by: Chanseok Oh <chanseok@google.com>

* Update .kokoro/downstream-client-library-check.sh

Co-authored-by: Chanseok Oh <chanseok@google.com>

* Update .kokoro/downstream-client-library-check.sh

Co-authored-by: Chanseok Oh <chanseok@google.com>

* Update .kokoro/downstream-client-library-check.sh

Co-authored-by: Chanseok Oh <chanseok@google.com>

* Update build.gradle

* chore: update comments

* chore: fix license year

* chore: add retry

* change timeout to 15 minutes.

* chore: revert display commands

* chore: update timeout to 100

* chore: remove retry

* Update downstream-client-library-check.sh

* Update downstream-client-library-check.sh

* Update downstream.yaml

* Update downstream-client-library-check.sh

Co-authored-by: Chanseok Oh <chanseok@google.com>

…1569)

* merge RefreshingManagedChannel & SafeShutdownManagedChannel into ChannelPool.

The eventual goal is to allow channel pool to safely add remove channels. The code has been refactored roughly as:
- SafeShutdownManagedChannel is now ChannelPool.Entry and ReleasingClientCall
- RefreshingManagedChannel has been merged into ChannelPool as a pair of functions scheduleNextRefresh & refresh

* migrate SafeShutdownManagedChannel tests

* migrate old tests and remove RefreshingManagedChannel and SafeShutdownManagedChannel

* fix test

* address feedback

* fix race condition on refresh()

* fix warnings in test

* Update gax-grpc/src/test/java/com/google/api/gax/grpc/ChannelPoolTest.java

Co-authored-by: Chanseok Oh <chanseok@google.com>

* Update gax-grpc/src/test/java/com/google/api/gax/grpc/ChannelPoolTest.java

Co-authored-by: Chanseok Oh <chanseok@google.com>

* handle race condition

* Update gax-grpc/src/main/java/com/google/api/gax/grpc/ChannelPool.java

Co-authored-by: Chanseok Oh <chanseok@google.com>

* introduce dynamic channel pool

* fix test after broken merge

* format

* address feedback

* remove unused import

* inline old factory methods

Co-authored-by: Chanseok Oh <chanseok@google.com>

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This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [gradle](https://gradle.org) ([source](https://togithub.com/gradle/gradle)) | patch | `7.4` -> `7.4.1` |

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deps: update dependency com.google.api.grpc:proto-google-common-protos to 2.8.0
deps: update dependency com.google.api.grpc:grpc-google-common-protos to 2.8.0
deps: update dependency com.google.api:api-common to 2.1.5
deps: update dependency com_google_protobuf to 3.19.4
deps: update dependency com.google.http-client:google-http-client to 1.41.5
deps: update dependency com.google.http-client:google-http-client-gson to 1.41.5
deps: update dependency com.google.guava:guava to 31.1-jre

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>