private byte[] readColorTable(final InputStream is, final int tableSize) throws IOException {
        final int actualSize = convertColorTableSize(tableSize);

        return BinaryFunctions.readBytes("block", is, actualSize, "GIF: corrupt Color Table");
    }
Extracts embedded XML metadata as XML string.
<p>

@param byteSource File containing image data.
@param params     Map of optional parameters, defined in ImagingConstants.
@return Xmp Xml as String, if present. Otherwise, returns null.
src/main/java/org/apache/commons/imaging/formats/gif/GifImageParser.java