presto-main/src/main/java/io/prestosql/util/JsonUtil.java/JsonUtil/createJsonParser
class JsonUtil:    public static JsonParser createJsonParser(JsonFactory factory, Slice json)
            throws IOException
    {
        // Jackson tries to detect the character encoding automatically when using InputStream
        // so we pass an InputStreamReader instead.
        return factory.createParser(new InputStreamReader(json.getInput(), UTF_8));
    }