swoole的定时器怎么应用

$server->tick(1000, function() use ($server, $fd) { 
 $server->send($fd, "hello world");
 });

<?php

$serv = new SwooleServer("0.0.0.0", 9501);

$serv->set(array(
 'worker_num' => 1, //worker process num
));

$serv->on('connect', function ($serv, $fd){
 echo "客户端 ".$fd."连接成功 
";
});
$serv->on('receive', function ($serv, $fd, $reactor_id, $data) {
 echo "客户端 ".$fd."发来消息：".$data."
";
 $serv->send($fd, 'Swoole已经介绍到您发送的消息: '.$data);
});
$serv->on('close', function ($serv, $fd) {
 echo "客户端 {$fd}关闭连接
";
});

$serv->on('WorkerStart', function ($serv, $worker_id){
 $serv->tick(2000, function(){
 echo "执行定时器任务 ".time()." 
";
 });
});

$serv->start();