msc {
  hscale = 1,
  width = "500";

  c [ label="Client" ],
  n [ label="Nginx" ],
  a [ label="Authorizer" ];

  ---  [ label="Good request" ];
  c->n [ label="Original request" ];
  n->a [ label="Mirrored request" ];
  a->n [ label="Authorizer decision (200)" ];
  n->c [ label="Client response (200)" ];

  ---  [ label="Bad request" ];
  c->n [ label="Original request" ];
  n->a [ label="Mirrored request" ];
  a->n [ label="Authorizer decision (400)" ];
  n->c [ label="Client response (403)" ];

  ---  [ label="Unsure request" ];
  c->n [ label="Original request" ];
  n->a [ label="Mirrored request" ];
  a->n [ label="Authorizer decision (401)" ];
  n->c [ label="Client response (401)" ];
}