:sig
String gz_compress(String src)

:params
src : uncompressed input bytes
return value : gzip-format compressed bytes

:see
>sys
gz_uncompress
zip_create
zip_read

:content
Compresses `src` and returns a gzip-format byte string.

The result is binary data. Store it in a file, send it with an appropriate content type/encoding, or pass it directly to `gz_uncompress()`.

```uce
String compressed = gz_compress("hello\n");
file_put_contents("/tmp/hello.txt.gz", compressed);
```

UCE writes a standard gzip wrapper around a deflate stream, including CRC32 and uncompressed-size footer fields.
