[Haskell-cafe] debugging snap app

Hi, I'm trying to get the debugging messages in snap-server in order to find the socket leaking in my snap app. I find the doc on snapframework.com says that setting an environment variable DEBUG=1 will enable the app to output the messages in stderr. But I don't get any. I installed the snap-server package using -fopenssl flag but without -fnodebug, so I think it's normal. Any idea on this? Eric