:meth:`.WMessengerOnionLayerProto.process` implementation

def _process(self, envelope, session, mode, **kwargs):
		""" :meth:`.WMessengerOnionLayerProto.process` implementation
		"""
		if mode == WMessengerOnionPackerLayerProto.Mode.pack:
			return self.pack(envelope, session, **kwargs)
		else:  # mode == WMessengerOnionPackerLayerProto.Mode.unpack
			return self.unpack(envelope, session, **kwargs)