xitep

why does the for-loop consume `evts`:

fn next_start_elem<R: Read>(evts: &mut Events<R>) -> Result<String, Error> {
    for evt in evts {
        if let XmlEvent::StartElement{ name, .. } = try!(evt) {
            return Ok(name.local_name);
        }
    }
    let _ = evts.text_position();
    Err(Error::UnexpectedEof)