clientv3/retry.go
func RetryKVClient(c *Client) pb.KVClient {
	return &retryKVClient{
		kc: pb.NewKVClient(c.conn),
	}
}
func RetryKVClient(c *Client) pb.KVClient {
	return &retryKVClient{
		kc: pb.NewKVClient(c.conn),
	}
}
// RetryKVClient implements a KVClient.