digraph A {
  0;
  1;
  2;
  3;
  5;
  7;
  
  
  0 -> 1 [label="S!Request(r: i32)", ];
  1 -> 2 [label="S?QuoteAlice(a: i32)", ];
  2 -> 3 [label="B!ParticipationBob(p: i32)", ];
  3 -> 5 [label="B?ConfirmAlice(c: i32)", ];
  3 -> 7 [label="B?QuitAlice(c: i32)", ];
  
  }
