我找到了我需要做的。

使用mediaRegion创建房间：

use Symfony\Component\HttpFoundation\Request;
use Twilio\Jwt\AccessToken;
use Twilio\Jwt\Grants\VideoGrant;
use Twilio\Rest\Client;

class VideoconferencingController extends Controller
{
    public function createAction(Request $request, $twilioRoomSid, $staffId, $roomName)
    {
        $twilioRoomSid = ('undefined' == $twilioRoomSid) ? null : $twilioRoomSid;

        $user = $this->getUser();

        $twilioAccountSid = $this->getParameter('twilio_account_sid');
        $twilioApiKey = $this->getParameter('twilio_api_key');
        $twilioApiSecret = $this->getParameter('twilio_api_secret');

        $now = new \DateTime();

        // Get or create room
        $twilio = new Client($twilioApiKey, $twilioApiSecret, $twilioAccountSid);

        if ($twilioRoomSid) {
            $room = $twilio
                ->video
                ->v1
                ->rooms($twilioRoomSid)
                ->fetch()
            ;
        }

        $createRoom = (!$twilioRoomSid || 'completed' == $room->status) ? true : false;
        if ($createRoom) {
            $room = $twilio
                ->video
                ->v1
                ->rooms
                ->create([
                       'mediaRegion' => 'ie1',
                       'uniqueName' => $roomName
                   ]
                )
            ;
            $twilioRoomSid = $room->sid;


            $staff = $this->findOr404('App:Staff', $staffId);
            $staff->setTwilioRoomSid($twilioRoomSid);
            $this->flush();
        }

        // Authorize room
        $identity = $user->getFullName();

        // Create access token, which we will serialize and send to the client
        $token = new AccessToken(
            $twilioAccountSid,
            $twilioApiKey,
            $twilioApiSecret,
            3600,
            $identity
        );

        // Create Video grant
        $videoGrant = new VideoGrant();
        $videoGrant->setRoom($twilioRoomSid);

        // Add grant to token
        $token->addGrant($videoGrant);

        // render token to string
        return [
            'token' => $token->toJWT(),
            'roomName' => $roomName,
        ];
    }
}