clientStream method
Implementation
Future<GenericMessage> clientStream(String service, String method,
List<GenericMessage> reqs,
{Map<String, String>? metadata, Duration? timeout}) async {
final m = _method(service, method);
final bound = reqs.map((r) => _BoundMessage(m.input!, r, _model)).toList();
final resp = _BoundMessage(m.output!, GenericMessage(m.output), _model);
await _channel.clientStreamCall(m.path, bound, resp, metadata: metadata, timeout: timeout);
return resp.generic;
}