code: public void setIncludeBody(boolean include) {
          addField(SubscribeOptionFields.include_body, FormField.Type.bool);
          setAnswer(SubscribeOptionFields.include_body.getFieldName(), include);
      }
docs: Sets whether the entity wants to receive an XMPP message body in
  addition to the payload format.
  
  @param include true to receive the message body, false otherwise