Node.js WebSocket consumer dropping Analytics Notification events

Consuming analytics/v2/events via WebSocket in Node.js ws library. The connection holds, but event throughput drops to zero after ~500ms. No error in the stream. Is this a client-side buffer issue or a server-side throttle?

const ws = new WebSocket('wss://api.mypurecloud.com/analytics/v2/events', { headers: { 'Authorization': `Bearer ${token}` }});
ws.on('message', (data) => console.log(data));

Getting no error logs, just silence.