initiator                                                    listener
    |                                                           |
    |   S Seq=0(Length=0) <MP_CAPABLE>, <TFO cookie request>    |
    | --------------------------------------------------------> |
    |                                                           |
    |   S. 0(0) ack 1 <MP_CAPABLE>, <TFO cookie>                |
    | <-------------------------------------------------------- |
    |                                                           |
    |   .  0(0) ack 1 <MP_CAPABLE>                              |
    | --------------------------------------------------------> |
    |                                                           |