+-------------------------------------------+
            |                                           |
            | Client                             Server |
            |                                           |
Handshake   |     --------- Q4S BEGIN ----------->      |
            |     <-------- Q4S 200 OK -----------      |
            |                                           |
Negotiation |                                           |
(Stage 0)   |     --------- Q4S READY 0---------->      |
            |     <-------- Q4S 200 OK -----------      |
            |                                           |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S 200 OK -----------      |
            |     <-------- Q4S PING -------------      |
            |      -------- Q4S 200 OK ---------->      |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S PING -------------      |
            |     --------- Q4S 200 OK ---------->      |
            |     <-------- Q4S 200 OK -----------      |
            |                    ...                    |
Negotiation |                                           |
(Stage 1)   |     --------- Q4S READY 1---------->      |
            |     <-------- Q4S 200 OK -----------      |
            |                                           |
            |     --------- Q4S BWITDH ---------->      |
            |     <-------- Q4S BWIDTH------------      |
            |     --------- Q4S BWITDH ---------->      |
            |     <-------- Q4S BWIDTH------------      |
            |                    ...                    |
Continuity  |     --------- Q4S READY 2 --------->      |
            |     <-------- Q4S 200 OK -----------      | app start
            |                                           |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S 200 OK -----------      |
            |     <-------- Q4S PING -------------      |
            |      -------- Q4S 200 OK ---------->      |
            |                                           |
Termination |     --------- Q4S CANCEL ---------->      | app end
            |     <-------- Q4S CANCEL -----------      |
            |                                           |
            +-------------------------------------------+