Gateway::sendToAll()出现stream_socket_client():错误

<?php
namespace app\index\controller;
require_once 'GatewayClient/Gateway.php';
// GatewayClient 3.0.0版本开始要使用命名空间
use GatewayClient\Gateway;
use think\Controller;
class Sendmsg extends Controller
{
    public function index()
    {
        // 向任意uid的网站页面发送数据
        /*Gateway::sendToClient('7f0000010b540000001f',json_encode(array(
            'type'      => 'send',
            'client_id' => 'this is ending all'
        )));//单个Client推送成功*/
        //$count = Gateway::isOnline('7f0000010b540000001d');
        Gateway::sendToAll(json_encode(array(
            'type'      => 'send',
            'client_id' => 'this is ending all'
        )));//报错stream_socket_client(): 
        //return $this->fetch();
    }
}
?>