How to extract request http headers from a request using NodeJS connect

I’d like to get the “Host” header of a request made using Node JS’s connect library bundle. My code looks like:

var app = connect()
  .use(connect.logger('dev'))
  .use(connect.static('public'))
  .use(function(req, res){

    var host = req.???

  })
 .listen(3000);

The documentation for connect is here but I don’t see anything detailing the API of the req object in the above code. http://www.senchalabs.org/connect/

Edit: Note a successful answer must point to the documentation (I need this to verify which version provided the API I’m looking for).