presto-local-file/src/main/java/io/prestosql/plugin/localfile/LocalFileRecordCursor.java/LocalFileRecordCursor/createNextReader
class LocalFileRecordCursor:        private BufferedReader createNextReader()
                throws IOException
        {
            if (!files.hasNext()) {
                return null;
            }
            File file = files.next();
            FileInputStream fileInputStream = new FileInputStream(file);

            InputStream in = isGZipped(file) ? new GZIPInputStream(fileInputStream) : fileInputStream;
            return new BufferedReader(new InputStreamReader(in));
        }