ProtobufCodec<DocApiT, ProtoT> build() {
            Objects.requireNonNull(encoderFn, "Encoder has not been set");
            Objects.requireNonNull(decoderFn, "Decoder has not been set");
            return new ProtobufCodec<>(apiClass, encoderFn, decoderFn);
        }
Implementation of MessageBus message request/response serialization built around Protocol Buffers.
documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/RoutableFactories80.java