The core result class that should be returned from each driver's process() function. This should be extended as Payment_Process_Result_DriverName and then have the appropriate fields mapped out accordingly.
Take special care to appropriately create a parse() function in your result class. You can then call _mapFields() with a resultArray (ie. exploded result) to map your results from parse() into the member variables.
Please note that this class keeps your original codes intact so they can be accessed directly and then uses the function wrappers to return uniform Payment_Process codes.