workerman定时器运行一段时间，多个定时器时间重叠

for($i=0;$i<=count($arr)-1;$i++){
 
    $uid = $arr->device_id;

    $command = $arr->command;

    $GLOBALS = Timer::add($arr->frequency, function()use($command ){

           Gateway::sendToAll(stripcslashes($command)); 

    });

    usleep(200000); 
 
}