Init() already forces the message.proto decoder configuration to "ProtobufDecoder" regardless of what is specified  (similar weirdness to your AMQP comment, no error is generated at the moment).  Technically the user should be able to specify MyFasterProtobufDecoder if they wanted.  We should probably require the user to specify the decoder in all cases and document that token and regexp parsers pass the data in the payload and message.proto data is passed in MsgBytes (or standardize that too)