Attach raw HTTP handler at the AppHost level to serve static files from a folder or folders

RawHttpHandlers.Add(req =>
      {
        if (!allowedPaths.Any(z => req.PathInfo.ToLowerInvariant().StartsWith(z.ToLowerInvariant())))
        {
          return null;
        }
        if (!req.HttpMethod.EqualsIgnoreCase("GET"))
        {
          return null;
        }      
        // Send back static file handler
        return new StaticFileHandler
        {
          VirtualNode = VirtualFileSources.GetFile(req.PathInfo)
        };
      });