code: @SuppressWarnings("unchecked")
    public <CONVERTER extends DefaultableConverter<S, T>> CONVERTER withDefaultValue(T defaultValue) {
      setDefaultValue(defaultValue);
      return (CONVERTER) this;
    }
docs: Builder method used to set the {@link Object default value} to use
  if the {@link Object value} to convert is {@literal null}.
  
  @param <CONVERTER> {@link Class type} of this {@link Converter}.
  @param defaultValue {@link Object default value} returned if the {@link Object value} to convert
  is {@literal null}.
  @return this {@link Converter}.
  @see #setDefaultValue(Object)