Stops the poller before an import begins. Idempotent — repeated calls before resume() do nothing.
Procedure with status no-poller, already-stopped, or stopped.
Resumes the poller after the queue drains. Fire-and-forget on the resume Promise to avoid dead-locking the queue-empty callback.
Procedure with status no-poller or poller-resumed.
Manages start/stop lifecycle of an injected TelegramPoller.