If set to a non-%NULL #GFileInfo object, and #GZlibCompressor:format is %G_ZLIB_COMPRESSOR_FORMAT_GZIP, the compressor will write the file name and modification time from the file info to the GZIP header.
If set to a non-%NULL #GFileInfo object, and #GZlibCompressor:format is %G_ZLIB_COMPRESSOR_FORMAT_GZIP, the compressor will write the file name and modification time from the file info to the GZIP header.