endCallAndResume method
Ends endSessionId and resumes resumeSessionId atomically, keeping
exactly one active call in the system call UI.
Returns 0 on success, negative error code on failure.
Implementation
Future<int> endCallAndResume({
required int endSessionId,
required int resumeSessionId,
}) async {
throw UnimplementedError('endCallAndResume has not been implemented.');
}