// a capture off the wire or from a pcap file
let capture = &[0, 0, 0xd, 0x0, 0x5, 0, 0, 0, 0x78, 0x56, 0x34, 0x12, 0, 0, 0, 0, 0x30, /* ... */ ];

// parse the radiotap header from the capture into a `Header` struct
let header: radiotap::Header = radiotap::parse(capture)?;

// get the length of the entire header
let length = header.length();

// Unpack the `rate` field if it is present
if let radiotap::Header { rate: Some(rate), .. } = header {
    assert_eq!(rate.to_mbps(), 24.0);
}

// using the length we can determine the rest of the capture
// i.e. IEEE 802.11 header and body
let rest = &capture[length..];