WebSocket URL Telnyx should stream audio to.
A complete XML document string.
telnyxStreamXml('wss://api.example.com/telnyx-stream');
// => '<?xml version="1.0" encoding="UTF-8"?>\n<Response><Stream url="wss://api.example.com/telnyx-stream" /></Response>'
Generate a Telnyx streaming XML response.
Telnyx primarily uses a REST API for call control, but this helper produces an XML acknowledgment document wrapping the stream URL for webhook responses that require XML.