Host A                                 Host B
   ------                                 ------
   ACK + MP_FASTCLOSE          ->
   [B's key]

   [RST on all other subflows] ->

                               <-         [RST on all subflows]


   Host A                                 Host B
   ------                                 ------
   RST + MP_FASTCLOSE          ->
   [B's key] [on all subflows]

                               <-         [RST on all subflows]