code: public void profileAttribute(final String name, String tag, final AttributeConverter<? extends Object> converter) {
          profileAttributes.put(name, tag);
          if (converter != null) {
              getConverters().put(name, converter);
          } else {
              getConverters().put(name, new StringConverter());
          }
      }
docs: Add an attribute as a primary one and its converter.
  
  @param name name of the attribute
  @param tag json reference
  @param converter converter