public function getCluster($projectId, $zone, $clusterId, array $optionalArgs = [])
    {
        $request = new GetClusterRequest();
        $request->setProjectId($projectId);
        $request->setZone($zone);
        $request->setClusterId($clusterId);
        if (isset($optionalArgs['name'])) {
            $request->setName($optionalArgs['name']);
        }

        $requestParams = new RequestParamsHeaderDescriptor([
          'name' => $request->getName(),
        ]);
        $optionalArgs['headers'] = isset($optionalArgs['headers'])
            ? array_merge($requestParams->getHeader(), $optionalArgs['headers'])
            : $requestParams->getHeader();

        return $this->startCall(
            'GetCluster',
            Cluster::class,
            $optionalArgs,
            $request
        )->wait();
    }