code: func (r *LiveReader) Err() error {
  	if r.eofNonErr && r.err == io.EOF {
  		return nil
  	}
  	return r.err
  }
docs: // Err returns any errors encountered reading the WAL.  io.EOFs are not terminal
  // and Next can be tried again.  Non-EOFs are terminal, and the reader should
  // not be used again.  It is up to the user to decide when to stop trying should
  // io.EOF be returned.