let (key, meta, file) = it.next().unwrap().unwrap();

        let (key, _, meta, file) = it.next().unwrap().unwrap();

        let (file_key, _, _) = it.next().unwrap().unwrap();

        let (file_key, _, _, _) = it.next().unwrap().unwrap();

                                if  contents_[c.end.0 as usize - 1] == b'\n' {

                                if contents_[c.end.0 as usize - 1] == b'\n' {

impl WriteChangeLine for &mut Vec<u8> {}

impl<W> WriteChangeLine for &mut W where W: WriteChangeLine {}
impl WriteChangeLine for Vec<u8> {}
impl WriteChangeLine for std::io::Stderr {}