title: node.js calculating bandwidth usage by domain
body: <p>How can I monitor the bandwidth usage of each domain using node.js as the web server?</p>
  
  <p>Does anyone know of an API call I haven't come across to do this?</p>
  
  <p>Or a module or another method which others have used in a multi-tenant environment where you are charging by bandwidth?</p>
  
  <p><strong>Update:</strong></p>
  
  <p>Does anyone know of a lightweight proxy / server which could be put in front of any web server (node.js, apache, etc) which can record these bandwidth stats by inspecting the domain?</p>