how to create demuxer from url instead of local file?

[snowway]

 // I want to create stream from rtmp:// rtsp:// http:// protocol
 let stream = File::open("./sample.mp4").unwrap();
 let io = IO::from_read_stream(stream);
 let mut demuxer = Demuxer::builder()
      .build(io).unwrap()
      .find_stream_info(None)
      .map_err(|(_, err)| err).unwrap();