Plack::Middleware::XSendfile - Sets X-Sendfile (or a like) header for frontends

  enable "Plack::Middleware::XSendfile";

You should use IO::File::WithPath or Plack::Util's set_io_path to add path method to an IO object in the body.

See http://github.com/rack/rack-contrib/blob/master/lib/rack/contrib/sendfile.rb for the frontend configuration.

Tatsuhiko Miyagawa