@Override
    public void writeToParcel(final Parcel dest, final int flags) {
        dest.writeParcelable(bitmapProvider, flags);
        dest.writeFloat(xAnchor);
        dest.writeFloat(yAnchor);
        dest.writeFloat(rotation);
        dest.writeInt(flat ? 1 : 0); // writeBoolean requires API 29
    }
if the marker should rotate together with the map (flat mode) or should be displayed as billboard popup.
main/src/main/java/cgeo/geocaching/models/geoitem/GeoIcon.java