SIGILL on calling any methods on SDPMedia obtained from an SDPMessage

The following code aborts with a SIGILL:

extern crate gstreamer_sdp as gst_sdp;
extern crate gstreamer as gst;

fn main() {
    gst::init();
    let sdp = "v=0\r\no=- 1938737043334325940 0 IN IP4 0.0.0.0\r\ns=-\r\nt=0 0\r\na=ice-options:trickle\r\nm=video 9 UDP/TLS/RTP/SAVPF 96\r\nc=IN IP4 0.0.0.0\r\na=setup:actpass\r\na=ice-ufrag:YZxU9JlWHzHcF6O2U09/q3PvBhbTPdZW\r\na=ice-pwd:fyrt730GWo5mFGc9m2z/vbUu3z1lewla\r\na=sendrecv\r\na=rtcp-mux\r\na=rtcp-rsize\r\na=rtpmap:96 VP8/90000\r\na=rtcp-fb:96 nack\r\na=rtcp-fb:96 nack pli\r\na=framerate:30\r\na=mid:video0\r\na=fingerprint:sha-256 DB:48:8F:18:13:F3:AA:13:31:B3:75:3D:1A:D3:BA:88:4A:ED:1B:56:14:C3:09:CD:BC:4D:18:42:B9:6A:5F:98\r\nm=audio 9 UDP/TLS/RTP/SAVPF 97\r\nc=IN IP4 0.0.0.0\r\na=setup:actpass\r\na=ice-ufrag:04KZM9qE2S4r06AN6A9CeXOM6mzO0LZY\r\na=ice-pwd:cJTSfHF6hHDAcsTJXZVJeuYCC6rKqBvW\r\na=sendrecv\r\na=rtcp-mux\r\na=rtcp-rsize\r\na=rtpmap:97 OPUS/48000/2\r\na=rtcp-fb:97 nack\r\na=rtcp-fb:97 nack pli\r\na=mid:audio1\r\na=fingerprint:sha-256 DB:48:8F:18:13:F3:AA:13:31:B3:75:3D:1A:D3:BA:88:4A:ED:1B:56:14:C3:09:CD:BC:4D:18:42:B9:6A:5F:98\r\n";
    let sdp = gst_sdp::SDPMessage::parse_buffer(sdp.as_bytes()).unwrap();
    let media = sdp.get_media(0);
    println!("{:?}", &media.unwrap().formats_len());
}

Changing formats_len to any other gst_sdp_media function has the same effect.

as far as I can tell, the error arises from the to_glib_none() function applied on the sdpmedia object.