public final MessageBuilder withBody(Object obj) {
        if (this.payload != null) {
            throw new IllegalArgumentException("Payload is exists.");
        }
        this.body = obj;
        return this;
    }
Configure message body object if the payload byte array is not exists.

@param obj
@return
@since 1.4.5
metamorphosis-client/src/main/java/com/taobao/metamorphosis/client/extension/spring/MessageBuilder.java