Good catch. It wasn't possible when I first wrote that line of code, but since I've changed the decoder mappings to come from config then it actually is possible. As I type this I also realize that I didn't actually set up any default decoders, so people have to specify this in the config even if they want the obvious choice of mapping JSON to our JsonDecoder and protobuf to our ProtobufDecoder. Maybe we should add such defaults?