This plugin provides a way to stream a file back to the user.

This is useful if you are creating a PDF or Spreadsheet document
dynamically to deliver to the user.

The file is read and printed in small chunks to keep memory
consumption down.

This plugin is a consumer, as in your runmode shouldn't try to do any
output or anything afterwards. This plugin affects the HTTP response
headers, so anything you do afterwards will probably not work. If you
pass along a filehandle, we'll make sure to close it for you.

It's recommended that you increment $| (or set it to 1), which will
autoflush the buffer as your application is streaming out the file.
