geopackage-sdk/src/main/java/mil/nga/geopackage/extension/style/IconCache.java
public Bitmap put(IconRow iconRow, Bitmap bitmap) {
        return put(iconRow.getId(), bitmap);
    }
public Bitmap put(IconRow iconRow, Bitmap bitmap) {
        return put(iconRow.getId(), bitmap);
    }
Cache the icon bitmap for the icon row

@param iconRow icon row
@param bitmap  icon bitmap
@return previous cached icon bitmap or null