toJson method
Converts to JSON.
type is only emitted when explicitly set. The bare
/realtime/transcription_sessions endpoint rejects unknown parameters;
the /realtime/client_secrets wrapper injects
'type': 'transcription' itself when serializing the embedded session.
Implementation
Map<String, dynamic> toJson() => {
if (type != null) 'type': type,
if (audio != null) 'audio': audio!.toJson(),
if (include != null) 'include': include,
};