The --rpc-pubsub-enable-vote-subscription flag may be used to enable it.
The current vote subscription is problematic because it emits a
notification for *every* vote, so hundreds a second in a real cluster.
Critically it's also missing information about *who* is voting,
rendering all those notifications practically useless.
Until these two issues can be resolved, the vote subscription is not
much more than a potential DoS vector.
* Add service to track the most recent optimistically confirmed bank
* Plumb service into ClusterInfoVoteListener and ReplayStage
* Clean up test
* Use OptimisticallyConfirmedBank in RPC
* Remove superfluous notifications from RpcSubscriptions
* Use crossbeam to avoid mpsc recv_timeout panic
* Review comments
* Remove superfluous last_checked_slots, but pass in OptimisticallyConfirmedBank for complete correctness
* Remove Blockstore member variable from BlockCommitmentCache
* Hoist is_confirmed_rooted() to its only caller
BlockCommitmentCache no longer depends on Blockstore
* Move BlockCommitmentCache to solana_runtime
* Switch subscriptions to use commitment instead of confirmations
* Add bank method to return account and last-modified slot
* Add last_modified_slot to subscription data and use to filter account subscriptions
* Update tests to non-zero last_notified_slot
* Add accounts subscriptions to test; fails at higher tx load
* Pass BankForks to RpcSubscriptions
* Use BankForks on add_account_subscription to properly initialize last_notified_slot
* Bundle subscriptions
* Check for non-equality
* Use commitment to initialize last_notified_slot; revert context.slot chage
* Add largest_confirmed_root to BlockCommitmentCache
* clippy
* Add blockstore to BlockCommitmentCache to check root
* Add rooted_stake helper fn and test
* Nodes that are behind should correctly id confirmed roots
* Simplify rooted_stake collector
* Add runtime methods to simply get status and slot
* Add helper function to get slot confirmation_count from BlockCommitmentCache
* Return cluster confirmations in getSignatureStatus
* Remove use of invalid get_signature_confirmation_status
* Remove unused methods
* Update pubsub to use cluster confirmations
* Fix test_check_signature_subscribe failure
* Refactor confirmations to read commitment cache only once
* Review comments
* Use bank, root from BlockCommitmentCache
* Update docs
* Add metric for block-commitment aggregations
Co-authored-by: Justin Starry <justin@solana.com>
