An enumeration type for specifying the mode of operation of a
Transformer instance, when wired into an Assembly.
This class cannot be instantiated; but its (only) two possible values
can be used for constructing Transformer elements:
- PRE_PROCESSING: to mean that the input data is first processed by
the current Transformer before being passed to the rest of the
- POST_PROCESSING: to mean that the input data is first passed to the
rest of the chain, and the resulting bytes are then processed by the