This should include:

• Use ByteToMessageDecoder rather than ReplayDecoder
• Decouple Decoder/Encoder from cache/exec operations invocation and channel IO related tasks. Decoder/Encoders should deal only with Bytes to Messages transformations, and could be possibly re-used in a eventual Netty Client
• Define more clearly Hot Rod Requests and Responses objects, and add a channel handler to operate on those messages by invoking cache or scripts operations
• Better separation version-wise of the DecoderXX/EncoderXX, avoiding using a single class for multiple versions