RPC Block Subscription (backport #21787)

[mergify]

This is an automatic backport of pull request #21787 done by Mergify.
Cherry-pick of 76098dd has failed:

On branch mergify/bp/v1.9/pr-21787
Your branch is up to date with 'origin/v1.9'.

You are currently cherry-picking commit 76098dd42.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   client-test/tests/client.rs
	modified:   client/src/pubsub_client.rs
	modified:   client/src/rpc_config.rs
	modified:   client/src/rpc_response.rs
	modified:   core/src/cluster_info_vote_listener.rs
	modified:   core/src/replay_stage.rs
	modified:   core/src/tvu.rs
	modified:   core/src/validator.rs
	modified:   replica-node/src/replica_node.rs
	modified:   rpc/src/optimistically_confirmed_bank_tracker.rs
	modified:   rpc/src/rpc.rs
	modified:   rpc/src/rpc_pubsub.rs
	modified:   rpc/src/rpc_pubsub_service.rs
	modified:   rpc/src/rpc_subscription_tracker.rs
	modified:   runtime/src/bank.rs
	modified:   transaction-status/src/lib.rs
	modified:   validator/src/main.rs

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   Cargo.lock
	both modified:   client-test/Cargo.toml
	both modified:   rpc/src/rpc_subscriptions.rs

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[solana-grimes]

😱 New commits were pushed while the automerge label was present.

[mergify]

automerge label removed due to a CI failure

[codecov]

Codecov Report

Merging #21992 (7161668) into v1.9 (02be3a6) will decrease coverage by 0.0%.
The diff coverage is 86.1%.

@@            Coverage Diff            @@
##             v1.9   #21992     +/-   ##
=========================================
- Coverage    81.2%    81.2%   -0.1%     
=========================================
  Files         515      515             
  Lines      143763   144193    +430     
=========================================
+ Hits       116864   117199    +335     
- Misses      26899    26994     +95     

[github-actions]

This PR has been automatically locked since there has not been any activity in past 14 days after it was merged.