GateWayWorker 如何控制流量

客户端发送消息密集的话，服务端就会报SendBufferToWorker fail.May be the send buffer are Overflow.
并且已经修改了php.ini 配置 Memory_limit=1024M.
因businessworker有写Mysql操作，会导致阻塞。
请问如何增加流量控制？

// gateway 进程，这里使用Text协议，可以用telnet测试
$gateway = new Gateway("tcp://0.0.0.0:8282");
// gateway名称，status方便查看
$gateway->name = 'YourAppGateway';
// gateway进程数
$gateway->count = 4;
// 本机ip，分布式部署时使用内网ip
$gateway->lanIp = '127.0.0.1';
// 内部通讯起始端口，假如$gateway->count=4，起始端口为4000
// 则一般会使用4000 4001 4002 4003 4个端口作为内部通讯端口 
$gateway->startPort = 2900;
// 服务注册地址
$gateway->registerAddress = '127.0.0.1:1238';
$gateway->maxSendBufferSize=4_1024_10324;
$gateway->onBufferFull = function($connection)
{
    $connection->pauseRecv();
    echo "bufferFull and do not send again\n";
};

$worker->onBufferDrain = function($connection)
{
    $connection->pauseRecv();
    echo "buffer drain and continue send\n";
}