sender;
    const sender2 = pc.addTransceiver('video').sender;
    const receiver1 = pc.getReceivers()[0];
    const receiver2 = pc.getReceivers()[1];

    assert_false(senderTransform.readable.locked, "sender readable before");
    assert_false(senderTransform.writable.locked, "sender writable before");
    assert_false(receiverTransform.readable.locked, "receiver readable before");
    assert_false(receiverTransform.writable.locked, "receiver writable before");

    sender1.transform = senderTransform;
  