docs: public Message setObject(Object obj) {
          if(obj == null) return this;
          if(obj instanceof byte[])
              return setBuffer((byte[])obj);
          if(obj instanceof Buffer)
              return setBuffer((Buffer)obj);
          try {
              return setBuffer(Util.objectToByteBuffer(obj));
          }
          catch(Exception ex) {
              throw new IllegalArgumentException(ex);
          }
      }