WebSocket URL Plivo should connect to.
A complete Plivo XML document string.
plivoStreamXml('wss://api.example.com/plivo-stream');
// => '<?xml version="1.0" encoding="UTF-8"?>\n<Response><Stream bidirectional="true" keepCallAlive="true">wss://api.example.com/plivo-stream</Stream></Response>'
Generate Plivo bidirectional streaming XML.
Instructs Plivo to open a bidirectional WebSocket stream and keep the call alive for the duration of the stream session. The stream URL is placed as element text content (not an attribute) per the Plivo XML spec.