pub fn new(bytes: [u8; 16]) -> Frame {
    let mut iter = bytes.chunks(4);
    Frame {
        id: BigEndian::read_u32(iter.next().unwrap()),
        flag: BigEndian::read_u32(iter.next().unwrap()),
        offset: BigEndian::read_u32(iter.next().unwrap()),
        length: BigEndian::read_u32(iter.next().unwrap()),
    }
}