Currently, setPayload() invoked on BytesMessage or NioMessage serializes the object into a byte array (byte buffer). However, the equivalent getPayload() returns the byte array/buffer, not the object.
The semantics should be:

• in: byte array, out: byte array
• in: object, out: object
  This can be implemented by adding a SERIALIZED flag: when an object is serialized into a byte array, the flag is set. When set, the byte array isde-serialized into an object on getPayload(), else the byte array is returned.