getResponse method
Implementation
@override
Future<String> getResponse({Message? message}) async {
_assertNotClosed();
if (message != null) await addQueryChunk(message);
// Serialize generation across sessions (mobile can't afford parallel
// generations; also keeps the shared event channel unambiguous).
return generationMutex.protect(
() => _platformService.generateResponseForSession(sessionId),
);
}