digraph state {
  edge [color=green];
  connect -> reqstart -> read -> reqend -> handlereq -> respstart -> write -> respend -> connect;
  edge [color=grey];
  reqend -> readpost -> handlereq [ label="POST" ];
  edge [ color=blue]
  respend -> reqstart [ label="keep-alive" ];
  edge [ color=lightblue]
  handlereq -> handlereq [ label="sub-request" ];
  edge [style=dashed, color=red];
  error -> close -> connect;
  error -> connect;
  handlereq -> error;
  read -> error;
  readpost -> error;
  write -> error;
  connect [shape=box];
}