Graph render race condition issues.

[arian]

Using Graph.render, there are some race conditions with graphviz.on("exit", …), where exit fires before the graphviz.stdout is ended.

So instead of using exit, you can use close in node 0.8. So a solution would be, in graph.js:373

  var version = process.version.split('.')[1]
  graphviz.on(version < 8 ? 'exit' : 'close', function(code) {
  // ...
  });