pingClient method
Ping the client (ping, either party may send it). Completes when the
client answers; throws TimeoutException (after sending
notifications/cancelled) when it does not.
Implementation
Future<void> pingClient(
String sessionId, {
Duration timeout = const Duration(seconds: 10),
}) async {
await _sendRequestToClient(sessionId, 'ping', const {}, timeout: timeout);
}