文件位置

libs/Swoole/Client/RPC.php

 protected function request($send, $retObj)
    {
        $retObj->send = $send;
        $this->beforeRequest($retObj);

        $retObj->index = $this->requestIndex++;
        connect_to_server:
        if ($this->connectToServer($retObj) === false)
        {
            $retObj->code = RPC_Result::ERR_CONNECT;
            return false;
        }
        //请求串号
        $retObj->requestId = self::getRequestId();
        //打包格式
        $encodeType = $this->encode_type;
        if ($this->encode_gzip)
        {
            $encodeType |= RPCServer::DECODE_GZIP;
        }
        //发送失败了
        if ($retObj->socket->send(RPCServer::encode($retObj->send, $encodeType, 0, $retObj->requestId)) === false)
        {
            $this->closeConnection($retObj->server_host, $retObj->server_port);
            //连接被重置了，重现连接到服务器
            if ($this->haveSwoole and $retObj->socket->errCode == 104)
            {
                goto connect_to_server;
            }
            $retObj->code = RPC_Result::ERR_SEND;
            unset($retObj->socket);
            return false;
        }
        $retObj->code = RPC_Result::ERR_RECV;
        //加入wait_list
        $this->waitList[$retObj->requestId] = $retObj;
        return true;
    }

问题：

$encodeType |= RPCServer::DECODE_GZIP;

这个|=是神马操作？