Res ↔ Response Object, 2nd Argument to HANDLER
res.status(code)
res.set(name, value)
res.cookie(name, value)
res.clearCookie(name)
res.redirect(status?, url)
res.send(body)
res.json(json)
res.jsonp(json)
res.end()
res.type(type)
res.format(object)
res.attachment
res.sendFile
res.links(links)
res.locals(view, locals?, callback)
res.render(view, locals?, callback)