Retrieves the gio.FileInfo constructed from the GZIP header data
of compressed data processed by compressor, or NULL if decompressor's
format property is not G_ZLIB_COMPRESSOR_FORMAT_GZIP,
or the header data was not fully processed yet, or it not present in the
data stream at all.
Retrieves the gio.FileInfo constructed from the GZIP header data of compressed data processed by compressor, or NULL if decompressor's format property is not G_ZLIB_COMPRESSOR_FORMAT_GZIP, or the header data was not fully processed yet, or it not present in the data stream at all.