GeoExt Printing - MapfishPrintProvider or PrintProvider?

Question

here is a working examples for a print preview with GeoExt 2:

http://geoext.github.com/geoext2/examples/printpreview/print-preview.html

but this example is using 'GeoExt.data.PrintProvider' while it is not in the source files: https://github.com/geoext/geoext2/tree/master/src/GeoExt/data

there is a MapfishPrintProvider.js instead.. which one i have to use ?

because I am having this problem:

Trouble in adding a print function to GeoExt MapPanel