@Override
    public ServiceInfo queryInstancesOfService(String serviceName, String groupName, String clusters,
            boolean healthyOnly) throws NacosException {
        return grpcClientProxy.queryInstancesOfService(serviceName, groupName, clusters, healthyOnly);
    }
@Test
    void testQueryInstancesOfService() throws NacosException {
        String serviceName = "service1";
        String groupName = "group1";
        String clusters = "cluster1";
        delegate.queryInstancesOfService(serviceName, groupName, clusters, false);
        verify(mockGrpcClient, times(1)).queryInstancesOfService(serviceName, groupName, clusters, false);
    }