@spec ack(pid(), term()) :: :ok

Acknowledges one delivered event and releases queue capacity.

@spec cancel(pid(), term()) :: :ok

Cancels one subscription without affecting its peers.

Returns a specification to start this module under a supervisor.

See Supervisor.

@spec close(pid(), term()) :: :ok

Gracefully closes one subscription.

@spec open(pid(), term(), term(), term(), pid(), term(), (map() -> boolean()) | nil) ::
  {:ok, term()} | {:error, term()}

Opens a subscription and sends an acknowledgment to the sink first.

@spec publish(pid(), map(), keyword()) :: :ok

Publishes a filtered notification with authorization rechecks.

@spec publish_sync(pid(), map(), keyword()) :: :ok

Publishes synchronously, completing after all current subscriptions are enqueued.

@spec start_link(keyword()) :: GenServer.on_start()

Starts the bounded subscription registry.

@spec stats(pid()) :: %{count: non_neg_integer(), queued: non_neg_integer()}

Returns bounded public counters for active subscriptions and queued events.