code: public void setFillColor(@ColorInt int color) {
      jsonObject.addProperty(FillOptions.PROPERTY_FILL_COLOR, ColorUtils.colorToRgbaString(color));
    }
docs: Set the FillColor property
  <p>
  The color of the filled part of this layer. This color can be specified as `rgba` with an alpha component and the color's opacity will not affect the opacity of the 1px stroke, if it is used.
  </p>
  <p>
  To update the fill on the map use {@link FillManager#update(Annotation)}.
  <p>
  
  @param color value for String