presto-parquet/src/main/java/io/prestosql/parquet/ParquetCompressionUtils.java/ParquetCompressionUtils/decompressGzip
class ParquetCompressionUtils:    private static Slice decompressGzip(Slice input, int uncompressedSize)
            throws IOException
    {
        if (uncompressedSize == 0) {
            return EMPTY_SLICE;
        }

        DynamicSliceOutput sliceOutput = new DynamicSliceOutput(uncompressedSize);
        byte[] buffer = new byte[uncompressedSize];
        try (InputStream gzipInputStream = new GZIPInputStream(input.getInput(), GZIP_BUFFER_SIZE)) {
            int bytesRead;
            while ((bytesRead = gzipInputStream.read(buffer)) != -1) {
                sliceOutput.write(buffer, 0, bytesRead);
            }
            return sliceOutput.getUnderlyingSlice();
        }
    }